alt Hacker NewsLLMs frequently hallucinate and go off on wild goose chases. It's admittedly gotten a lot better, but it still happens.
From that perspective alone the session would be important meta information that could be used to determine the rationale of a commit - right from the intent (prompt) to what the harness (Claude code etc) made of it. So there is more value in keeping it even in your second scenario
I try to use AI incremental and verify each result. If it goes mad, I just revert and start over. It's a bit slower but ensures consistency and correctness and it's still a huge improvement over doing everything manually.