In other words, nobody asks: "is BTC a better investment than USD?". That's a strawman.
They don't need to ask if BTC is a better investment because people don't traditionally use USD as an investment on its own. They do it against another currency. Not because the dollar does not increase in value on its own, but it rarely happens, and not in a significant way to be an investment.
It would be crazily stupid for an American in America to hold USD in the hope that the value increases. But it would not be stupid for an Indian to convert his INR to USD in the hope that the USD would gain against his currency.
Funny how you also ignored the part where I said I have received BTC for my work and have BTC as an option of payment for clients who are willing to pay in BTC. You also ignored the part where I said I've paid payments in BTC. I'm talking cross-border payments that would have needed an intermediary, more fees and more time.
You can't tell me you have not seen services and businesses online, at least, that accept Bitcoin as a means of payment. So what do you call that? Isn't that Bitcoin as a currency?
I have told you that a thing doesn't need to be only a currency, or only an asset, or only a commodity, or only a store of value. Maybe in the traditional sense, it may be so, but when a thing has the characteristics of more than one, then it can be both or even more.
In fact, it is because Bitcoin is a currency with superior qualities that makes it a great asset today. If Bitcoin were built just as an asset and nothing more, it most likely wouldn't have been what it is today. An asset has to give value to have value. If you take away the currency side of Bitcoin, then what is it? It's nothing, it's just a beautifully written code.
This is what people who criticise Bitcoin as an asset miss. They ask questions like "So what does Bitcoin give?" Since gold is a precious metal, and equity is part of a company. That is because they ignore the currency aspect of it, and that is what gives Bitcoin value.
If the USD had a "halving" to reduce its supply and a limited supply alone, you would see that people would buy it and hold, even though it is centralised, hoping for its value to increase because reducing the supply of a thing when the demand remains the same or increases, will increase the price of that thing. But this won't stop the USD from being a currency. Would it?
So the better question should be "Is Bitcoin a better currency than USD?"
And yes, it is. Unlike USD (and all other fiat currencies), with Bitcoin, you don't need a bank or any other payment system to send money to another person, as long as the recipient is willing to accept BTC. You can send that money to any country without any "middleman".
You don't have to worry about the devaluation of your currency. Your savings won't be eaten by inflation.
It may not be among the most popular currencies or the most used, but when you compare it against any other fiat, it's superior.
Your argument should be on the fact that people no longer use Bitcoin for what it "truly" is or what it was "meant to be", since most people use it as an investment or store of value. But with the genius of Bitcoin, everybody is free to use it however they see fit. They can decide to hold, use it to buy pizza, use it to preserve their wealth or whatever way they see fit. It is not a cult that says, "You must use it like this"