On the other hand reviewing and correcting text is often harder and requires more attention than writing it yourself: it's easy to miss something, and just assume "ah I think that's fine" (when it's actually not).

All things considered, an awkward sentence or two isn't really that much of a big deal compared to an incorrect assertion that was missed in review.

I also don't think GPT-4 is necessarily that brilliant at writing copy, but I don't really know how good/bad US government officials are so I can't really compare, but in other parts of the world I haven't really that much of an issue with it.