Em dashes are commonly used in most countries that speak English. I get the feeling that people from the USA don’t use them often and now have tarnished the use of them.
Way too many bullets -> way too many emojis -> way too many em dashes
They aren't a complete rarity by any means but still relatively uncommon compared to the typical punctuation one sees in routine usage.
I loved em dashes back in high school and my English teacher would have definitely returned an assignment with a lot of red marks if I used em dashes as frequently as an LLM (speaking from experience).