It's funny, I've noticed my own writing has been getting a lot sloppier the past couple years just so that my writing doesn't get mistaken for AI. I actually used to use "--" pretty much all the time when I was young (granted I didn't go full em-dash, just the ascii version). It does make me kind of sad though, because writing in really short sentences (as one example) is actually a great way to make your writing easier to digest.