You argue that any system would be easier if we had all learned it in preschool, then turn around and claim some massive, mind boggling amount of effort that must be expended by Americans to use ounces, miles, and all sort of other yucky units you might need a lot of energy to use, but Americans have been learning, alongside SI, since preschool. Just like how you don’t likely struggle with 7 day weeks of 24 hour days with 60 minute hours.

So which is it?