AI models can't possibly contain everything to the depth one might require on a niche topic. Additionally, the less training data available, the more egregious the hallucinations become.
I've worked on some pretty niche things where the only way to get actual info is painstaking manual search queries based on a tree of keyword combinations. Those barely come up because search is (practically) dead, but when I'd ask AI the same questions or to find the same queries, it would simply make up confident answers.
AI is only truly helpful for the common denominator of very well documented and often discussed topics.