For instructions you really care about, yes of course you review the assembly output! Usually when you're doing SIMD or want to check atomics are doing what you expect.
You can do that with LLMs for the parts you really care about too. The LLMs aren't regenerating the codebase from scratch every time, so the results stick around.
Only if it's not too byzantize to understand what part you should look at
The AI can tell you where to look. It's really good at this. It's actually a lot better at analyzing code than it is at writing it.