I’m not even American but this is way less intuitive for everyday use. I don’t need some abstract measure of how efficient my car is being. My fuel tank is measured in liters, when I fill up i pay by the liter, I want to know how far I can go on x liters. Not have to do a bunch of mental math to reverse the equation for my gas tank with 40 liters in it. I have 40l, I can go x*40 km. Mental multiplication is way easier than mental division.