Also, if I adopt some clever StoatOverflow thing into my code, I can link back (and I do) to the SO post where I got it, so it's easy to trace what I was thinking. I don't think there's a similar thing to point people back at an LLM-generated answer, unless you C&P the whole thing (plus prompts) somewhere.

Search results also produce the effect andrewducker alluded to: you can skim different results and get a feeling for some level of disagreement. This is rather flattened by LLMs, and of course they render it impossible to examine the source material yourself. It breaks traceability.