Nobody divides miles by feet.
Yeah. Because it’s a shitty system.
It will be the same for kilometers.
Except it’s not.
People will either say „half a kilometre“ or „500 meters“, because that’s something you can actually easily calculate …
And your GPS will tell you „turn left in 100/200/etc m“, or and not „in a quarter of a mile“…
No… Actually, the person you’re talking to is correct. We switch back and forth in metric all the time, fluidly, because it’s easy. The things you’re describing and many more are normal parts of the metric system, and your flat assumption that it never happens because you assume it’s too hard and unnatural is kind of a solid demonstration of how metric is superior.