2. There is plenty of evidence for this elsewhere on the site, and we do encourage people to try it because like with a lot of AI tools, YMMV.
You're totally right that PR reviews go a lot farther than catching issues and enforcing standard. Knowledge sharing is a very important part of it. However, there are processes you can create to enable better knowledge sharing and let AI handle the issue-catching (maybe not fully yet, but in time). Blocking code from merging because knowledge isn't shared yet seems unnecessary.
You're totally right that PR reviews go a lot farther than catching issues and enforcing standard. Knowledge sharing is a very important part of it. However, there are processes you can create to enable better knowledge sharing and let AI handle the issue-catching (maybe not fully yet, but in time). Blocking code from merging because knowledge isn't shared yet seems unnecessary.