It might well be useful if the RIGHT proofs are evaluated and proven. Figuring out what will be useful has always been a real challenge in math. Finding certain symmetries and mappings between problems in different domains, might well be useful even if they aren't well understood? That has always been another part of the work of mathematicians. Of course there are those who just work on the beauty of things, and few in the 80s would have thought that prime factoring number theory or elliptic curves would be the basis for modern communications and banking.

That said, getting a point solution and not knowing the path to get there, is certainly much less useful, and generalization is much harder. Again, more work for mathematicians, but maybe without the easy "I solved it" proof metric for rewards. Goodhart's law strikes again.