You have to define what you mean by "useful"?

Monero's fungibility is excellent, but the transactions-per-second ain't that great right? Also Proof of stake is inherently more sustainable in a resource-constrained world: you don't want to replace banks by something more wasteful thank banks...

For my money's worth, and clearly talking my own book here, the decidedly zero-hype Algorand is the useful crypto at 20k TPS, this is the Visa/Mastercard territory where things get interesting. As for fungibility, it will have to be some democratically controlled thing I think...