To be fair, LLMs usually use em-dashes correctly, whereas I think this document misuses them more often than not. For example:
> This can be extraordinarily powerful for summarizing documents — or of answering more specific questions of a large document like a datasheet or specification.
That dash shouldn't be there. That's not a parenthetical clause, that's an element in a list separated by "or." You can just remove the dash and the sentence becomes more correct.
I don't know whether that use of the em-dash is grammatically correct, but I've seen enough native English writers use it like that. One example is Philip K Dick.
Perhaps you have—or perhaps you've seen this construction instead, where (despite also using "or") the phrase on the other side of the dash is properly parenthetical and has its own subject.
I think you're thinking of british-style "en-dashes" – which is often used for something that could have been separated by brackets but do have a space either side – rather than "em" dashes. They can also be used in a similar place as a colon – that is to separate two parts of a single sentence.
British users regularly use that sort of construct with "-" hyphens, simply because they're pretty much the same and a whole lot easier to type on a keyboard.
> This can be extraordinarily powerful for summarizing documents — or of answering more specific questions of a large document like a datasheet or specification.
That dash shouldn't be there. That's not a parenthetical clause, that's an element in a list separated by "or." You can just remove the dash and the sentence becomes more correct.