One observation I ran across on the use of the em-dash ("—") was that if AI was given training data from writers that were considered good/great, and those writers tended to use em-dashes, then it would be unsurprising that AI 'learned' to use the character.
So the observer said humans should, if they already did so in the past, continue to use the em-dash now and going forward if it was already part of their 'personal style' in writing.