My head did 36" divided by 2, so 18", minus 12 1/16", so 5 and 15/16". That is harder than working with quarters or fifths of meters, but easier than thirds or sixths of meters.
I don't know which is better. Considering how nothing stops you from doing decimal inches or fractional meters, but people rarely do that, both ways seem fine.
33.3 cm is easy to measure out, and 99.9 cm is exactly 1 mm short of 1 meter, well within tolerances for carpentry. Narrower than the mark left by your pencil.
But also like, we have calculators…