"but that doesn't mean there aren't some great ones out there. Cryptocurrency isn't going away. If you believe all this negative news nonsense saying it's going to 0, you're just being played again like all the fools that believed it was going to go up forever and bought at 20 grand."
Sure, there may well be use cases for blockchains, but does buying Bitcoin give you exposure to them?
Anyone can write their own blockchain or fork an existing one, and many people have and the alternatives mostly address some of the problems that bitcoin has in terms of speed and scalability.
Another thing. Isn't TfL's Oyster Card a cryptocurrency of sorts? It isn't stored on a blockchain obviously, but it has been very successful. If you had bought £5 of Oyster Credit in 2003, how much would it be worth now? The answer is, it would be worth £5. Buying a bitcoin is exactly the same as buying Oyster credit.