It's not a waste of time though. Those warnings and clippy lints are there to improve the quality of the code and to find bugs.

As a human I can just decide to write quality code (or not!), but LLMs don't understand when they're being lazy or stupid and so need to have that knowledge imposed on them by an external reviewer. Static analysis is cheap, and more importantly it's automatic. The alternative is to spend more time doing code review, but that's a bottleneck.