(I haven't used AI much, so feel free to ignore me.)
This is one thing I've tried using it for, and I've found this to be very, very tricky. At first glance, it seems unbelievably good. The comments read well, they seem correct, and they even include some very non-obvious information.
But almost every time I sit down and really think about a comment that includes any of that more complex analysis, I end up discarding it. Often, it's right but it's missing the point, in a way that will lead a reader astray. It's subtle and I really ought to dig up an example, but I'm unable to find the session I'm thinking about.
This was with ChatGPT 5, fwiw. It's totally possible that other models do better. (Or even newer ChatGPT; this was very early on in 5.)
Code review is similar. It comes up with clever chains of reasoning for why something is problematic, and initially convinces me. But when I dig into it, the review comment ends up not applying.
It could also be the specific codebase I'm using this on? (It's the SpiderMonkey source.)