A foot being 12 inches makes fractions work really well in US units (as well as a mile being 8 x 10 x 11 x 6 foot). And with it working so well, many people don't seem to be able to imagine to work without them.

In metric a meter isn't as nicely divisible. Of course we get around that by subdividing 1.2m or 1.5m instead (or 0.8, kitchens and lots of furniture is designed in outer dimensions that are fractions and multiplies of 0.8 meters). But that only works well if you write them out add decimals, because saying "this cupboard is 1/2 0.8 meter wide" is just silly