Modern tech makes a lot of this irrelevant. I can drive from US into Canada, spend 5 seconds going through my cars settings, and have everything displayed in km, even the km I have left in the tank. It's like when coders use constants in their program, and only have to remember the constant name while the number it represents can change in a config header or something. The program still runs as normal while silently using the new value.
It's not really worth caring about. Not in everyday life. I'd say differently if you were a scientist or engineer. Metric should be the measurement system of all STEM.