there are algorithmic ones where supply is automatically minted and burned to keep price steady. and then there are "reserve-backed" ones where some entity (ostensibly) holds dollars or whatever the fuck 1:1 with tokens. I'm not sure if the latter somehow proves reserves, but it seems like there would always be an oracle problem.
Discussion
Oh right, I always forget there are distinctions between some of them.
And yes, the oracle problem lurks as one of the greatest issues I can think of. Not to mention assumption of stability of reserves ðŸ¤
Guess I'll have to someday get around to seeing what elements of blockchains exactly are involved, as I often feel unequipped to go very deep when asked about them