except currently the main usecases for cryptocoins are to buy illicit goods and services online. I remember when OpenBazaar was a thing. It even somehow managed to get an iOS app despite it being ridiculously easy to find listings for lbs of cocaine

Ya, I'm not a big fan of that use case, and I agree it's a problem. But I hold Bitcoin as a hedge against inflation. It tends to do better than gold, and is way easier to transact and store.