I disagree. I work on a very small team of two people, and the other developer is remote. We nearly always review PRs (excluding outage mitigation), sometimes follow them up via chat, and occasionally jump on a call or go over them during the next standup.

Firstly, we get important benefits even when there's nothing to talk about: we get to see what the other person is working on, which stops us getting siloed or working alone. Secondly, we do leave useful feedback and often link to full articles explaining concepts, and this can be a good enough explanation for the PR author to just make the requested change. Thirdly, we escalate things to in-person discussion when appropriate, so we end up having the most valuable discussions anyway, which are around architecture, ongoing code style changes, and teaching/learning new things.

I don't understand how someone could think that async code review has almost zero value unless they worked somewhere with a culture of almost zero effort code reviews.