Documentation is one place where humans should have input. If an LLM can generate documentation, why would I want you to generate it when I can do so myself (probably with a better, newer model)?

I definitely want documentation that a project expert has reviewed. I've found LLMs are fantastic at writing documentation about how something works, but they have a nasty tendency to take guesses at WHY - you'll get occasional sentences like "This improves the efficiency of the system".

I don't want invented rationales for changes, I want to know the actual reason a developer decided that the code should work that way.

That's great if those humans are around to have that input.

Not so much when you have a lot of code from 6 years ago, built around an obscure SDK, and you have to figure out how it works, and the documentation is both incredibly sparse and in Chinese.

Because it takes time and effort to write documentation.

If people __can__ actually read undocumented code with the help of LLMs, why do you need human-written documentation really?