It doesn't look imprecise per se. These are just the letterforms you can get out of wood with a router.

I'm curious why it's associated with blueprints, but I have no insight into the history of applying type to blueprints.

EDIT: to answer my own question, it has to do with the scribing device used for Leroy letters. One of which was used to source this font. Nice description of how it was used here https://kleinletters.com/Blog/leroy-lettering-by-jim-and-mar...