I agree that people tend to work with the system that they have become accustomed to. However I don't think it hurts to have people aware of the fact that the sytem they are using can be misleading.
The fact that the majority of the world's population uses a particular system does not mean it is logical or sensible or efficient or anything else. It usually means it is the one that has become entrenched through years, decades or centuries of use.
I think it is generally accepted that Beta video was technically better than VHS, but VHS won out through sheer weight of numbers.
The qwerty keyboard is used almost universally even though more efficient keyboard layouts such as the Dvorak keyboard exist. The qwerty layout was designed to be inefficient. It helped stop mechanical problems with early manual typewriters. We are stuck with the inefficient qwerty because so many people are familiar with it.
I think we may have to put up with some people using mpg or km/l not because they are logical but because people are familiar with them.

__________________

1973 Series III LWB 1983 - 2006
1998 300 Tdi Defender Trayback 2006 -
- often fitted with a Trayon slide-on camper.