I really like the argument about misinformation vs testing. I'm not totally sold on "you can just see it", but I do think something like TDD could suddenly be really productive in this world.

I've found autocomplete via these systems to be improving rapidly. For some work, it's already a big boost, and it's close to a difference in kind from the original IntelliSense. Amusingly though, I primarily write in an editor without any autocomplete, so I don't experience this often. But I do, precisely for the throwaway code and lower-value changes.

Finally, it's not clear to me that the distinction is between systems programming and scripting. My sense is that Chat GPT and similar are (a) heavily influenced by the large corpus of Python, so it's better at it than C and (b) the examples here involved more clever bit manipulation than most software engineers ever interact with.