You are wrong. Bitcoin is a number. Number is not a currency but mathematical object. A currency is legally enforceable instrument which originated from loan contracts in a specific country.

In a banking system all money comes from debt. So when new money, dollars for e.g., are created, in the same time, some individual, company, or organization became legally obligated to pay these dollars back. That's the nature of debt - it must be paid. In other words, every dollar that is currently in circulation, must eventually be returned to FED or commercial banks. That means that those who received dollar loans and put dollars into circulation are forced to get these dollars back by selling their goods or services to people who have dollars. Otherwise they will fail to make necessary loan payments and as a result they will be taken to court and the banks will seize their property.
So due to the fact that dollars come from debt and debt must be paid, people who have dollars do not have just a piece of paper with some numbers on it, but instead, they have legally enforceable rights to goods or services of people who received the loans. Fiat is therefore a legal instrument that grants its holder with legal path to restore the intrinsic value in some economic goods.

Cryptocurrencies on the other hand, didn't originated from debt, so nobody is legally obligated to use them to repay the debt, which is why cryptocurrency holders have nothing but empty numbers. And if a situation occurs where nobody wants to accept cryptocurrencies in exchange for goods and services, no legally enforceable right exist upon which they can get some kind of value out of them. Hence, all that these people have is hope and faith that someone will exchange their numbers for fiat money or economic goods, which is by definition a Ponzi scheme.

This is not an argument against the claim that Bitcoin is a Ponzi. In a Bitcoin scheme people renounce their economic goods with intrinsic value or money that offers them the legal path to restore such value, all in exchange for empty numbers in their wallets. And that's a textbook example of a Ponzi scheme. But like I said, people will learn this the hard way.

When I presented arguments like the one in the the video below, people just ignored them. Now, they will learn the hard way what it means to be a part of a Ponzi scheme.

Bitcoin And Cryptocurrencies - Ponzi Schemes Dressed Up And Sold As Money
https://youtu.be/gcNngl8fCUY

EDIT:

Why bitcoin is a Ponzi scheme:

In a banking system all money comes from debt. So when new money, dollars for e.g., are created, in the same time, some individual, company, or organization became legally obligated to pay these dollars back. That's the nature of debt - it must be paid. In other words, every dollar that is currently in circulation, must eventually be returned to FED or commercial banks. That means that those who received dollar loans and put dollars into circulation are forced to get these dollars back by selling their goods or services to people who have dollars. Otherwise they will fail to make necessary loan payments and as a result they will be taken to court and the banks will seize their property.
So due to the fact that dollars come from debt and debt must be paid, people who have dollars do not have just a piece of paper with some numbers on it, but instead, they have legally enforceable rights to goods or services of people who received the loans. Fiat is therefore a legal instrument that grants its holder with legal path to restore the intrinsic value in some economic goods.

Cryptocurrencies on the other hand, didn't originated from debt, so nobody is legally obligated to use them to repay the debt, which is why cryptocurrency holders have nothing but empty numbers. And if a situation occurs where nobody wants to accept cryptocurrencies in exchange for goods and services, no legally enforceable right exist upon which they can get some kind of value out of them. Hence, all that these people have is hope and faith that someone will exchange their numbers for fiat money or economic goods, which is by definition a Ponzi scheme.

Why cryptocurrencies never were and never can be money: cryptocurrencies don't have value on their own and as such they cannot serve as a measure of value.

A measure of value is pretty simple concept. It expresses the value of one thing in terms of another. In principle anything that has value on its own can serve as a measure of value. For example a toothpick. Although the intrinsic value of a toothpick is very small it is not zero since toothpick has practical utility.  So perhaps the iPhone is worth 500,000 toothpicks. A shirt may be worth 25,000 toothpicks. One hour of guitar lesson may be worth 15,000 toothpicks. And so on. Since it has value on its own toothpick acts as a measure of value and we can use it to compare the value of different goods and services. The same is true for fiat currencies. Since fiat currencies are legal claims connected to property of borrowers through loan contracts we can easily measure how many units of newly created money corresponds to a particular good, service, claim or other asset. This legal connection to property is the reason why fiat currencies can be used as a measurement of value. This is also the reason why the exchange rates of fiat currencies maintain relatively stable and have low volatility. It is precisely because these currencies are legally connected to real property and real tangible goods.

On the other hand, in the case of cryptocurrencies, besides having zero intrinsic value they are not legally connected to property. In other words there are no enforceable contracts or collateral behind them. There is no legal claim that is measured with them. There is no right which is granted to their holders. All there is, is open source software which generates stores and transfers empty numbers between members. Given the fact that number is an abstract mathematical object thet has no value on its own it is impossible in principle for cryptocurrencies to serve as a measurement of value. This is the reason why crypto currencies never were and never can be money. Also this is the reason why their price is so volatile unstable and can jump from few cents to several thousand dollars. Since they have zero intrinsic value and no legal connection to property their price depends entirely on the number of people that enter into the scheme.

You must educate yourself about the basics of banking system because this statement of yours shows that you have utterly no clue about how the accounting mechanics of bank credit creation works.

When financial corporation, such as a bank, grants a loan to a customer, and thus creates new money, the loan contract is shown as an increase in assets: the bank now has an additional claim on debtors — this is the borrower's legal obligation to repay the loan (which is secured by the collateral of specified movable or immovable property). But, together with the increase in assets, the newly created money appears as a positive entry on the liability side of the bank's balance sheet. IOWs, whenever some firm or person receives the newly created money from the borrower's bank account, the value of this money comes from the fact that it represents the bank's legal liability which is backed by borrower's legal obligation to repay the loan. So, when banks create money, this money is backed by either - legally enforceable obligation of borrowers to repay their loans or the collateral of specified movable or immovable property that a borrower offers as a way for a bank to secure the loan.

That is why, if a situation occurs where nobody wants to accept fiat money in exchange for goods and services, those who received the loans are legally forced to accept it, otherwise they would be unable to settle their obligations to the bank and a legal action would be taken against them or the bank would seize the collateral to recoup its losses. Additionally, the value of fiat money comes from the fact that it is legal tender for all debts, public and private, which is especially important today when countries have high tax-to-GDP ratio.

So saying that fiat money is worthless, simply shows the lack of understanding of how legal, monetary and banking system work.

The only thing which is entirely worthless is Bitcoin. Since Bitcoin is neither legal tender nor backed by any legally enforceable obligation, if a situation occurs where nobody wants to accept Bitcoins in exchange for fiat, goods or services, they can neither, be used to pay taxes nor any legal action can be taken by their owners to get some kind of value out of them. That is why Bitcoin is nothing but a modern ponzi scheme, a collection of empty numbers on the internet that will collapse just as all other ponzi schemes have collapsed.

That is not true. Money has intrinsic value because it is backed by debt, while debt is backed by imovable or movable property. In the past, monetary system was based on a gold standard. Today, monetary system is based on a property standard.

Of course that you can exchange Bitcoins for fiat, goods and services - this is their basic purpose, that's why they even exist in the first place and this is how those who inveneted them are coming into possession of real property in exchange for nothing.

What I am arguing is that Bitcoins are just emptly numbers without any real value to its owner - he can't eat them, drink them, wear them, drive them, sit on them, enter into them, please the aesthetic senses with them or made a legal case to come into possession of goods and services with such capacities, like in the case of fiat. Simply put, those who invented Bitcoin received real market values in the form of goods, services and fiat, in exchange for some empty numbers recorded in a public ledger called a blockchain. Can this blockchain be used to satisfy human needs? No. Can this blockchain be used to establish a legal case and get some kind of value out of it? No. Thus, Bitcoin is neither good nor service nor money not asset, but instead it is some empty number on the internet.

I already answered this. Since Dollars are backed by debt, and debt is backed by collateral of specified immovable or movable property, if nobody wants to accept dollars those who recieved the loans are forced to accept them since otherwise they would not be able to repay their debts, a legal case would be established against them, and the bank would take their property. No such legal obligations are behind Bitcoins as the software that creates them is not a legal entity which can have legal rights and obligations. That's why, on their own, Bitcoins are completely useless.

What is the point of calling Bitcoin an asset when it is so obvious that it is not. An asset is defined as a resource with economic value that can provide future benefit. Bitcoins are just numbers on the internet and you can't eat them, drink them, wear them, drive them, sit on them, enter into them, please the aesthetic senses with them,... nor do they represent legal rights(like fiat does) which ultimetly lead to goods and services with the properties just mentioned. Thus, Bitcoins on their own are completely useles with regards to benefits and that's why they aren't an asset.

The difference between numbers on a bank account and on a Bitcoin address is like the difference between numbers on an utility bill and numbers on an empty paper. If you don't pay the bill, you will get a legal notice for non payment of the bill from the company lawyer and further a case will be established against you. Hence, numbers on an utility bill have legal power. Numbers on an empty paper do not have legal power. The same is true for numbers on a Bitcoin address - if nobody wants to accept them in exchange for goods, services and fiat, no legal case can be made to get some kind of value out of them - meaning, they possess no legal power. In the case of numbers on a bank account, if nobody want or accept them in exchange for goods and services, those who received the loans would not be able to repay their debts and a legal case would be established against them, so that those who recieved "the numbers on a bank account"(those with deposits) can be settled in some imovable or movable property.

As we can see, fiat is an asset in its true sense - an asset with the legal power that can be used and exchanged as a true market value. Bitcoin on the other hand is... NOTHING. So, people are buying 'nothing' with the hope that the price of 'nothing' will increase. Clearly, this is an antithesis of market exchange and the definition of an irrational behaviour.

Price is NOT the same as value. Value of an entity comes from its capacity to satisfy human wants. Price on the other hand is the amount of money given in payment for something. Value describes the benefits of ownership which include utility - the pleasure or satisfaction gained by consumption of a particular good or service; and rights - the ability to gain goods or services in the future(Dollars). With Bitcoins you don't have such utility as they are neither goods nor services nor rights. Bitcoins are just empty numbers. The mere fact that people are willing to buy them has nothing to do with their value.

Value comes from utility - the capacity of an entity to satisfy human wants. Number on your Bitcoin address does not have such capacity. If nobody want or accept Bitcoins you are unable to take legal action in order to get some kind of value out of them that can lead to satisfying of human wants. Hence, Bitcoin doesn't have any value of it's own. If people are buying X, and X doesn't have value of it's own, than this is irrational behaviour and not something that gives value to X.

If nobody want or accept Dollars than those who received the loans and exchanged them for goods and services would not be able to settle their obligations to the bank. As a result, the bank would seize the collateral to recoup its losses and finally, those who have deposits would get some immovable or movable property.

Now it's your turn, if nobody want or accept Bitcoins what can you do with them?  

So, if nobody wants to accept Bitcoins in exchange for dollars, goods or services, what can you do with them?

Unlike numbers on a bank account, which represent legal liability of the bank and are backed by the collateral of specified real estate or other debt instrument that a borrower offers as a way for a bank to secure the loan, the numbers on a bitcoin address are completely void of any legal liability since software that creates them is not a legal entity which can have legal rights and obligations.

So basically, people are paying huge amounts of money to get some empty numbers which are then recorded in a public ledger on the internet. If nobody wants to accept these numbers in exchange for dollars, goods or services, they are as useless as a random number that I write on a piece of paper.

On the other hand, since dollars in a bank account are bank's liability, if nobody wants to accept dollars in exchange for goods and services, they will be settled over time through the legal system by transferring real assets from those who have received loans from the bank, since loans are secured by the collateral of specified immovable or movable property and they represent bank's assets. This comes from the fact that obligation to repay the debt would not vanish if nobody wants to accept dollars. Since the borrower received real assets for its dollars, in the absence of dollars the borrower's debt must also be settled by real assets. Alternatively, since dollars that are in circulation were exchanged for goods and services by some borrower and since he is obligated to repay his debt in dollars, if nobody wants to accept dollars the borrower is the one who is forced to accept them in exchange for goods and services otherwise he is unable to settle his obligation to the bank. Besides being backed by borrower's collateral, dollars are also backed by banks' capital and the ability to pay taxes. As we can see, dollars on their own, have real measurable value, just like goods or services.

Bitcoins on the other hand, don't have value on their own, and if nobody wants to accept them in exchange for dollars, goods or services, no legal action can be taken by their 'owners' to get some kind of value out of them. As such, Bitcons are just empty numbers on the internet, which means that people are exchanging real values for literally nothing.