The problem to me doesn’t seem to be the em dashes but rather the multiple people around you that actively talk about “being an intellectual writer“ and how they need to signal it with their choice of punctuation. Frankly they sound ridiculous. But again, that has nothing to do with the actual punctuation itself. Writing off a writing tool because of two people you agree are ridiculous doesn’t seem like the right way to respond to their behavior.

I’ve used it for literally decades for both formal and informal writing. On social media and in text messages. It is a very useful way to communicate/pace your sentences.