Proof of useful work feels like it's one and a half steps removed from discovering seigniorage and reinventing money.

I mean that's just proof of work. PoUW is just an attempt at converting some of that work into something worthwhile and not pointless hash grinding.

There's a lot of re-inventing the wheel in the cryptocurrency space but on the formal academics side of the space people are very cognizant of what they are working on and their work is focusing on improving very specific properties of consensus algorithms.