didn't even notice the em dashes to be honest, i noticed the contrast framing in the second paragraph and the "It's impressive how" for its conclusion.

as for the "assumption" bit, yeah fair enough. was just curious of AI usage online, this wasn't meant to be a dig at anyone as i know people use it for translations, cleaning up prose etc

No offense taken, but realize that good number of us folks who have learned English as a second language have been taught in this way (especially in an academic setting). LLMs' writing are like that of people, not the other way around.