One fundamental problem at this point is that coin sponsors and the enthusiastic coin owner-boosters want massive price growth so they can strike it rich. But as a medium of exchange price stability is a very nice property.

In terms of price stable crypto-currencies there's tether, which is looking very much like a scam, and some kind of complicated ethereum contract token the name of which slips my mind at the moment.

The stellar network is supposed to be able to be used to make payments without necessarily involving stellars (except to fund the transaction). But the anchors and trust web needed to do that don't exist (yet?)