It depends. Em dashes in news articles and written publications? Definitely expected. Em dashes on social media or reddit? Either someone who works in typesetti

It depends. Em dashes in news articles and written publications? Definitely expected. Em dashes on social media or reddit? Either someone who works in typesetting, or an LLM. Most likely an LLM, giving the dying nature of printed media. Only typography nerds and professional printers care about things like these. Popular media, even modern professional media, hasn't been paying all that much attention.