Most of my code review comments are along the lines of "what does this do" -- the primary question I'm asking in an in-person review. My goal for a review is to pre-emptively answer the questions I'd ask if I had to fix bugs in the code. This frequently exposes bugs because it requires the author to consider their code from a different perspective.
Maybe it's the code under review: I work in games and was reviewing a lot of code from juniors, so I'd often be asking questions intended to get them thinking about their technical design and we had very little rigor.
In my eyes, the biggest upside of in-person is how it reduces mental drain from back-and-forth. A conversation is comfortable instead of the digital equivalent of repeated red ink all over your work.
> Over a decade of experience with merging enthusiastically approved, hopelessly broken code
Or maybe you're commenting on the code reviewers you've worked with rather than your own experience as a reviewer?