They don't solve "the problem of trust" but instead the much narrower "how can a group of entities, who mutually do not trust each other, have a ledger whose state they can all agree on". Crypto loosely solves trust in trustless environments, but I'm having a hard time finding where that is nicely applicable. Most transactions already require a certain base level of trust. So, yeah, dog shit has a pretty clear use case and value whereas NFTs do not. Would love counter-examples for that though. The best I've found is in the art world, where having a token that corresponds to a given work would make it much easier to track the "official" version (vastly reducing the value of any more than one forgery substantially), and I guess the various traders and dealers don't have a high degree of trust in one another so this public and distributed ledger would help with that. Obviously a lot of other problems but it at least demonstrates a hint of some value.