The ideal would be useful work that is a public good - no one can profit from it individually (other than by using it as a PoW), but the world benefits from it in some way.
https://en.wikipedia.org/wiki/List_of_distributed_computing_...
E.g. see discussion of information goods here https://en.wikipedia.org/wiki/Public_good#Challenges_in_iden...
PoW mining just raises the capital cost to control the network without ever improving the speed or functionality. It's a system that increases the waste as time progresses.