The pound is a promise by the UK government.
FTT, CEL, VGX, etc.. are a promise by a crypto exchange.
Turns out, one of those promises is worth more than the others.
But those tokens, backed by promises with zero value, were traded back and worth between the exchanges and booked on the balance sheet as though they had actual value. And as soon as that premise was tested, it was found to be obviously false, and the house of cards collapsed.
Now SBF is currently in prison awaiting trial. Why?
Because he did naughty things with
actual real money.
Specifically he diverted USD that customers sent to one company to a different one.
That is why he is having the book thrown at him, he committed crimes with real money rather than fake money.
Of course there are other crypto currencies, just as there are other fiat currencies
Yes, that was the point I was making. The exchanges didn't fail because of Bitcoin, or Ethereum.