As per sibling comment, I think my "old school" wording is getting misconstrued here. I did mean 20th-century "old school", i.e. typewriters... Is the Late Middle Ages considered "old school"? :)

Agreed that in terms of precedent, typesetters had moveable type dashes for their presses.

> the fifteenth century, and "em" and "en" were standard printing widths in moveable type. People who write CSS still recognize em as a width.

This is very interesting!