Nitpicking can be automated by a linter, then reviews can actually sit back and review more important things like high-level design and scalability

as if peer reviews could actually spot bugs that tests can't catch

There can't be bugs if there are no tests to catch them! Ofc you can also automate test coverage standards. But PRs are sometimes the only way to catch bugs, even and especially with senior devs in my experience bc they are lazy and will skip writing tests, or write useless or bare minimum tests just to check off code standards and merge on ahead