I feel like it was Lewis Carroll where I was first exposed to long dashes. I could be misremembering though.

Made me look! 265 in _Alice's Adventures in Wonderland_.

I use em dashes and semicolons and ellipses and parentheses a lot, although I barely make the leaderboard¹. My doctor says I'm human. In the pre-Unicode era of Usenet and mailing lists I used ‘ -- ’ for a long dash.

¹ https://www.gally.net/miscellaneous/hn-em-dash-user-leaderbo...