Anytime I do this — and I did it long before AI did — they are always em dashes, because iOS/macOS translates double dashes to em dashes.
I think there may be a way to disable this, but I don’t care enough to bother.
If people want to think my posts are AI generated, oh well.
There is also the difference in using space around em-dashes.
> Anytime I do this — and I did it long before AI did — they are always em dashes
It depends if you put the space before and after the dashes--that, to be clear, are meant to be there--or if you don't.