I don't know if there's a clarification about 3d art and if this one allowed it will just tolerate people to don't put any huge effort on the contest because as many people stated they can just generate it everywhere and then submit it to the contest thread. I do hope there's separate contest between personal created arts and 3d ones so that this will not go unfair to any artist who join the contest.
That's exactly the point of AI art. It decreases the effort required to generate mind-blowing art. For example, NFTs took off like crazy recently primarily because of this kind of tech.
AI art should be utilised in a legit manner though which implies generating art in a 100% unique manner without plagiarising others works.
Roobet already limit their Art contest, and whatever your art is you can join though theres a rule that you should not still others work, and if you guys have evidence that a participant steal a work online by using that AI system then you can just report it, so far upon seeing the participants it looks like they hand drawn it, and theres a lot of good art already.