I grew up ob forums where em-dashes and semicolons were fairly common—Harry Potter roleplay forums! In fact, that's how I learned most of my English; probably where some of my expression style developed.

Em-dashes are a great way to signal something—thought or extra context—were inject into normal sentences flow. It can make the text appear more conversational

I realise Harry Potter roleplaying forums are not really your "normal" crowd though lol