I think its worth saying two things:
1. This result is very far from showing something like "human mathematicians are no longer needed to advance mathematics".
2. Even if it did show that, as long as we need humans trained in understanding maths, since "professional mathematicians" are mostly educators, they probably aren't going anywhere.
> ... are mostly educators, they probably aren't going anywhere
Educator business survived so far, only because they provided in-person interactive knowledge transfer and credentials - both were not possible by static sources of knowledge such as libraries and internet. But now all that is possible without involvement of human teachers.
I wouldn't say professional mathematicians are mostly educators. The educating that mathematicians do even at graduate level to non-future-mathematicians can mostly be done (not fully at parity due to depth of understanding that we accumulate but close) by non professional mathematicians. Most of the education is to other current/future mathematicians in my limited opinion.