The DFT paper is an example against AI 'strip-mining'. The paper introduces a new method, and researchers are already trying to improve on it. If anything, the OpenAI dump re-vitalized that branch of study.
Agreed. Basically, if you don't make any effort to understand the proofs and you just look at the final answer, it will look like this proof dump is "strip mining" entire branches of math. But this is a pretty short-sighted way of looking at the issue: there will be plenty of novel approaches to be uncovered here.
It doesn't really introduce a new method though. It introduces a new model of computation (exact-precision complex arithmetic being O(1)). Toss in an O(1) modulus operation and your average undergrad can actually get O(n) DFT for any desired result accuracy. Sneaking infinite compute into a primitive operation isn't new or especially interesting.