Well you would also have to look up the conversion factor for tons, pounds, and miles, to SI units, so I dunno what you’re on about.

My chevy uses SI displacements and all that. Roll back 70 years and, sure, they used imperial displacments and volumes.

So what? The time to do the math is a trivial portion of the investment, and only done to convert units for consumer volume and for publicity.

Most uses are more simple, like putting 1 oz of 2-4,D in a gallon with a nice glop of chemsurf.

And the history of math, counting, and measurement is endless and sublime, they got shit done with primitive tools and measures.