I would argue that there just isn't much gain in terms of speed of delivery, because you have to proofread the output - not doing it is irresponsible and unprofessional.

I don't tend to spend much time on a single function, but I can remember a time recently where I spent two hours writing a single function. I had to mentally run all cases to check that it worked, but I would have had to do it with LLM output anyway. And I feel like reviewing code is just much harder to do right than to write it right.

In my case, LLMs might have saved some time, but training the complexity muscle has value in itself. It's pretty formative and there are certain things I would do differently now after going through this. Most notably, in that case: fix my data format upfront to avoid edge cases altogether and save myself some hard thinking.

I do see the value proposition of IDEs generating things like constructors, and sometimes use such features, but reviewing the output is mentally exhausting, and it's necessary because even non-LLM sometimes comes out as broken. Assuming that it worked 100% of the time: still not convinced it amounts to much time saved at the end of day.