That was a wonderful ride.
TL;DR: In the late 1800's, a need for machine-assisted engraving developed. A font was created in tandem with an engraving machine. Over the next hundred years, a huge portion of engraving machines came with something related to this font by default.
It's the ancestor of many technical drawing fonts because early lettering guides were made using these engravers. It's the basis for many classic keyboard caps and typewriter keys. It's on every nametag from the 1930s to 1990s. But most of all, if you wanted a durable sign and weren't a graphic designer, it's what you got for most of the last century.