Until LLMs came around, I rarely saw other people use interrupting/parenthetical clauses at all, em dash or not. Kind of the same with semi-colons even. Or bold or subtle italics.

I’ve always enjoyed the style that em dashes and semi-colons add to a piece of writing and it was what made me start using them. It was always notable to me when I noticed them in someone’s else’s writing, which was always rare.