But that's not what a PR summary is best used for. I don't need links to exact files, the Diff/Files tab is a click away and it usually has a nice search feature. The Commits tab is a little bit less helpful, but also already exists. I don't need an AI telling me stuff already at my fingertips.

A good PR summary should be the why of the PR. Not redundantly repeat what changed, give me description of why it changed, what alternatives were tested, what you think the struggles were, what you think the consequences may be, what you expect the next steps to be, etc.

I've never seen an AI generated summary that comes close to answering any of those questions. An AI generated summary is a bit like that junior developer that adds plenty of comments but all the comments are:

    // add x and y
    var result = x + y;

Yes, I can see it adds x and y, that's already said by the code itself, why are we adding x and y? What's the "result" used for?

I'm going to read the code anyway to review a PR, a summary of what the code already says it does is redundant information to me.