I (and my team) work remote and don't quite agree with this. I work very hard to provide deep, thoughtful code review, especially to the more junior engineers. I try to cover style, the "why" of style choices, how to think about testing, and how I think about problem solving. I'm happy to get on a video call or chat thread about it, but it's rarely necessary. And I think that's worked out well. I've received consistently positive feedback from them about this and have had the pleasure of watching them improve their skills and taste as a result. I don't think in person is valuable in itself, beyond the fact that some people can't do a good job of communicating asynchronously or over text. Which is a skills issue for them, frankly.
Sometimes a PR either merits limited input or the situation doesn't merit a thorough and thoughtful review, and in those cases a simple "lgtm" is acceptable. But I don't think that diminishes the value of thoughtful non-in-person code review.
> I work very hard to provide deep, thoughtful code review
Which is awesome and essential!
But the reason that the value of code reviews drops if they aren't done live, conducted by the person whose code is being reviewed, isn't related to the quality of the feedback. It's because a very large portion of the value of a code review is having the dev who wrote the code walk through it, explaining things, to other devs. At least half the time, that dev will encounter "aha" moments where they see something they have been blind to before, see a better way of doing things, spot discontinuities, etc. That dev has more insight into what went into the code than any other, and this is a way of leveraging that insight.
The modern form of code review, where they are done asynchronously by having reviewers just looking at the code changes themselves, is not worthless, of course. It's just not nearly as useful as the old-school method.