Found this out in school when someone wrote some less than acceptable words on the board in permanent marker. The teacher scribbled over it with drywipes, waited a few seconds and wiped it away.
They said it was because essentially drywipe marker is a permanent marker with solvents.
37 year old American here. I was raised learning both and I can and have built things in both systems. Hell I've even mixed them on occasion. I own a metric tape measure and a metric/inch tape measure, and several inch tape measures.
Specifically for woodworking, I vastly prefer working in fractional inches, for a whole stack of reasons but mainly in the wood shop, you find yourself dividing by 2 or 3 way more often than 5 or 10. Working in a dozenal system in powers of 2 makes more sense for that than working in a decimal system in powers of ten. It's just easier to buy rough lumber at 1 inch thick, use 1/4" of it to mill it flat and parallel so you have 3/4", and now if you need to do a half-lap joint it'll be 3/8" or a tenon will be 1/4".
I still don’t get how they can live with such a retarded measurement system.
We can't.
Scientists do everything in metric, but that's where it stops.
Food industry tries to label everything both ways, so we all get some minimal exposure; but this is like expecting to learn French in Canada just by hanging around. Machinists cope by using thousandths (of an inch), but still have to translate to work with standard screw dimensions. Bakers do everything at multiples of cups or pounds, so fractions don't really come up. Housing framers use, maybe, down to the half or quarter inch and have easier to read tape measures for this; story-boards and tick-sticks are used to avoid measuring entirely.
If it wasn't for raw materials (across the board) being sold in nominal empirical sizes, I would sooner just use the metric system.
Meanwhile, the home kitchen is at war. Recipe books have everyone else dicking around with all the crazy fractional volume and weight measures. Either you're a virtuoso with these, or you're terrible at it and burn every meal - there is no middle ground. This might explain our relationship with restaurant food.