Nothing wrong with CMOS/APA/MLA dashes, I quite like them but usage in LLM prose has ruined it for me. AP dashes are weird, too much horizontal spacing, looks horrible and can really erode typographic color sometimes. "International" Oxford/Cambridge spaced dashes is nicest.

The funny thing is at both extremes, either none or indiscriminate use of dashes like in TFA, is a canary of "human writing".

People (including comments here) often attribute LLM use to prevalence in training data but it is probably far less common in the wild than we are led to believe, the more likely scenario is that whatever text-to-text normalization tools used ended up inserting whatever their idiosyncratic typographic styles were.