They haven't 'found' a single practical use case other than for some speculators who think they have a 'store of value'.
Reading this thread it's clear Web3 doesn't really have a use case either, it's more like a concept.
These have many parallels in industry - there are tons of products that never got made because they didn't make a whole lot of sense even though they were cool. The difference being, people can chose to spend their own time on these things now if they so choose and a lot of people do.
It's like a distributed technical artistic counter-cultural social movement except the artists believe they're doing something more practical than they probably are.
