I do not really know the answer, but I am inclined to agree with Brendan McKay's answer which I will just paraphrase as in the long term, none.

As a counterpoint though, I do not think this will mark the end of human mathematicians since I regard mathematics as a fundamentally human endeavor. For example, even though computers have surpassed humans in chess playing ability, I still enjoy playing chess (against fellow humans) and watching chess (played between two humans). For example, Anand's missed tactic against Carlsen in Game 6 of the 2014 World Chess Championship was very dramatic to watch live.

As another example, one can imagine that eventually we will be able to design a team of robots that can beat any human football team. This does not mean humans should stop playing or watching football.

For me, mathematics is more than just knowing which mathematical claims are true or false. There is a human community of mathematicians that one should actively engage in by presenting at conferences, writing papers/books that are humanly digestible, mentoring other humans, etc.