So, like voltage, it’s another case where Americans invented something and Europeans doubled down.
But let's pretend your warped view of history is reality...that happened 100 years earlier. If Europeans are so enlightened atop those tall horses, maybe don't do it again and 10x worse?
In addition, I wasn't referring to the Holocaust...but the entire continent's shared sick desire to kill themselves off for 10km of border movement or literal dreams of world conquest.
No surprise that basing your units on the physical properties of water doesn't give you very human-friendly results. Their only good unit is kilograms/grams. Edit: actually not even that.
Pounds have a nice granularity for every day stuff: a 3 pound laptop and a 2 pound laptop are significantly different, but both are “about a kilo”.
On the other end, a gram is such a small amount that I can only perceive it in multiples, whereas I have a pretty good idea of how much an ounce is.
But oh, if you're willing to say "and a half" you might as well be willing to say .7 kilo.
There's no real overall advantage, you just picked a couple very specific numbers. You can always pick very specific numbers to make any system look better/worse.
Speaking of which, there's nothing stopping us from using something like SI prefixes with customary units, for example kilofeet. We just don't need to.