> they are excellent at synthesizing requirements and documentation

Hard disagree.

I'm sure you think it's excellent if you're the person who was supposed to be writing it, but your opinion is influenced by your happiness that you didn't have to do it.

LLMs are good at generating the kind of documentation that shouldn't be written in the first place, because it's just a wordier rephrasing of what's already in the code, and therefore wastes the time of anyone who reads it.

LLMs suck at documentation for the same reasons the author identifies as the reasons why they suck at programming. The additional value I'm looking for when reading documentation is mostly the mental models.