There are several purposes for such a mining device:

• Some of these usbminers were once profitable (albeit, this is no longer the case)
• They make great learning tools
• They can be used for testing, for example when you're developing new pool software
• They can be used as lotto mining devices (altough the odds of hitting a block are really low)
• They can be used to insta-mine a new altcoin
• They can be used as a conversation starter, for example: if one of your friends sees a comaq's flashing light and asks what that's for, you can start a conversation about bitcoin
• They do quite well on some testnets, not bitcoin's testnet specifically, but other ones

Like HeRetiK already said, it's not only theoretically possible, it's even rather easy.
There are even scripts to help you brute force such a seed: https://github.com/gurnec/btcrecover/blob/master/docs/Seedrecover_Quick_Start_Guide.md

davis196 is right, it's completely up to the user wether they chose to use an online wallet or not.

There are plenty of desktop and hardware wallets out there that are extremely user-friendly. There is no reason why a new user should ever resort to storing their funds in an online wallet or exchange.
I've said it before and i'll say it again: if you're not the (only) one in controll of your private keys, you're not in controll of your funds!

Sure, if you use a desktop, paper or hardware wallet, it's up to YOU to make sure it's properly encrypted and backupped! if you fail to keep your wallet's seed or private key a secret, or you're ignorant enough to keep only one copy, you only have yourself to blame if you lose everything.

I have a habit of cheaping out on fees when i move funds between my own wallets. Nowadays, i always opt-in RBF, which makes it very easy to create a double spending transaction with a higher fee and broadcast it, but about a year ago, i did have to create new transactions doublespending the unspent outputs used and input of my own transactions several times. It was during the spam attack and the astronomical fees, and before opt-in RBF was adopted in my wallet, so many of my low-fee between-my-own-wallet transactions got "stuck". doublespending was the fasted way of fixing these problems.

It can be done, but like i said: if you wait for 1+ confirmations, the transaction can no longer be "cancelled" this way.

I always just reboot the printer after i've printed paper wallets... It's memory, it should be cleared when the printer is turned off.

But NeuroticFish is right, if you're really paranoid, you can fill up the printer's memory with a useless pdf, just to be sure... Or you can put the printer on top of a big pile of wood in your garden and burn it

You can't cancel or revert a transaction.

However, there are a couple "tricks" you can pull while a transaction is UNCONFIRMED.

For example, you can create a (very) low-fee transaction, and broadcast it to as little nodes as humanly possible. Then, create a new transaction, using the same unspent outputs as input but funding a completely different address as the first transaction. You can create this secondary transaction with a much higher fee and broadcast it to as many nodes as possible.
If you do this, there is a decent chance a miner will put the second transaction into the block he's currently working on instead of the first one. And once one of those transactions ends up in a valid, broadcasted block that's been added to the blockchain, the other transaction is automatically "voided". It's using unspent outputs that are no longer in the UTXO set, so the unconfirmed tx becomes invalid.

If you're setting up a service, it's always a good idear to wait for at least 1 confirmation before sending goods or services. For expensive products, you might even chose to wait 3+ confirmations ( 6+ for the really paranoid shop owners). Once a transaction has a couple of confirmations, there is no way of cancelling or reversing it.

The problem is that 99,99% of the cloudmining companies are really just ponzi scams disguised as a mining website. The 0.01% "real" cloudmining companies sell you 100% of their risk for a small cut of the profits. Sure, you can make a profit with them, but since you're carrying all the risk anyways, the profits are rather small in comparison.

Also, the eco-friendly aspect does not work... As a matter of fact, it would be more eco-friendly to put an ASIC inside your house at wintertime and mine by yourself (on a pool or solo), so you can recuperate the heat and use less fossil fuels to heat your house. Cloudmining isn't something magical that happens in an utopian dreamworld. The 0.01% real cloudmining companies actually bought real asic's that use real power and caused real pollution when they were produced. The difference is that they usually scaled up, so they have an advantage with the power price, cooling, racks, security,... However, they usually don't recuperate the heat, and they have some overhead that you wouldn't have if you ran 1 ASIC in your living room (very noisy tough), for example: you wouldn't need extra cooling, you wouldn't need special power failover mechanisms, you wouldn't need security guards. So, all these factors would make it more eco friendly to mine by yourself compared to cloud mining.

I would doubt this, very much... I don't foresee the price to be near the price of BTC. If it was, thousands of people would fire up their GPU mining rig, and drive the diff waaaay up. You'd still be making money in this (utopian) case, but i doubt it would be a "goldmine" (pun intended )..

Don't get me wrong, i'd love to see a world where the bitcoin hashrate would become decentralised again, but i very much doubt that bitcoin gold will be the answer. I just think it'll become an altcoin, like many before, with the possible exception their blockchain will keep btc's transaction history up untill the point of the actual fork.
That's just my opinion tough, i can be wrong, but i doubt it...

De bitcoin prijs is gewoon afhankelijk van vraag en aanbod.
De vraag naar bitcoin is hoog, zowel voor beleggers, geïntresseerden als voor mensen die effectief van bitcoin gebruik willen maken. De vraag naar bitcoincash is laag, voor zover ik weet zijn enkel beleggers licht geintresseerd in deze munt.

Daar komt natuurlijk nog bij dat de hashrate (dus ook de diff) hoger is voor bitcoin, en dat deze dus als veiliger gezien word, ook het dev team achter bitcoin word als betrouwbaarder gezien door de community. Dit alles draagt dus ook bij tot een grotere vraag, dus een hogere prijs.

Correct, enkel een laatste aanvulling, want er was nog 1 vraag van de OP onbeantwoord:
Er zullen uiteindelijk inderdaad evenveel BCC als BCH in circulatie zijn (ongeveer 21 miljoen) op het moment dat de block reward effectief 0 zal worden.

I'm from a EU country and helt far less than $1000 at the time i got the notice i needed enhanced verification.
I was lucky since converting everything to LTC and then withdrawing straight away still seemed to work at that time.

The fact  enhanced verification is easy means nothing to me. Out of principle, i will always try to avoid sending anybody identifying information that can be stolen and abused later on. I'm not a criminal, i just don't trust an US private company with a picture of me holding an id card or utility bill.
As long as bittrex is asking for information that can be leaked/hacked/abused/... i will no longer use their services.

I defenately wasn't thinking about ethereum... There are a couple dozen coins that  use POS as their algorithm. Examples are Diamonds, blackcoin, Magicoin,...
I don't really follow altcoin development, but ethereum switching from POW to POS is something i haven't heared (yet).

I funded an address i generated with my ledger nano S. I'm not a big fan of holding any funds on exchanges or online wallets to begin with. It just happened that i exchanged some ETH i got for a job a couple weeks ago, so i still had some funds i forgot to withdraw on their exchange.

i can verify that i to got a notice that i needed to enable enhanced verification before i could withdraw from bittrex.
I immediately exchanged whatever funds i still had with them to LTC and withdrew. I was lucky, cause it seems this worked for me.

I will probably not be using them anymore in the future, since i do not want to send images of myself holding my id and utility bill to a US company.

you can read up on the POS (proof of stake) algorithm.
It is designed to reward people that hold (stake) a certain amount of altcoins for a certain time.

This way, you can create passive income, however, it's only a limited number of altcoins that use POS, if you pick an altcoin to stake, and you gain 10% in one year, but in the same time, the altcoin's price goes down 50%, you end up with more altcoins but with less actual value.

I don't actually know a lot about ethereum, but it does look like they have a hd wallet:
https://github.com/meth-project/eth-hd-wallet
- use this at your own discretion, i have never used above wallet -

HD = deterministic, meaning they use a derivation path to derive private keys from an xprv. I think you need a HD wallet, so you can export the xpub and derive addresses from it. SPV means it's basically a "light" wallet that only download the block headers, and uses a thirth party service for everything else.

So... You are the campaign manager, and you yourself act as escrow for the funds in the address you posted. It might have been better if you worded it that way, it would avoid confusion around this topic.
Usually, an escrow is a green trusted, longtime member that has handled hundreds of bitcoins during multiple transactions, thus can be trusted with 2 BTC of campaign funds.

I wish you good luck with your campaign tough!

you say you now have an escrow, but it just seems the only thing you did is you posted a link to an address that is funded.
Who is your escrow, and can he/she post a signed message stating he/she is acting as your escrow?

There are loads of payment gateways, however, WHY do you think running your own nodes is not the best option?

I'd peronally go for a node with a locked wallet, or i'd generate an xpub from an SPV wallet and use this xpub to derive payment addresses, especially when we're talking about bulk transactions. This way you can controll every aspect, and you don't have to rely (and pay) an external partner.

Your account will not be gone if you don't access it for 3 months. Your post count will not go down, your activity will not go down,...
The only thing that will happen is that your profile will show a warning after your first login after a long idle time... something like "warning: this user just became active after a long time" (don't remember the exact wording).