Try being in aviation in the US. At any given time I can be juggling:
Distance:
statue miles, nautical miles
Speed:
miles per hour, feet per second, feet per minute, knots, mach, feet per mile (climb rate)
Pressure:
inches of mercury, millibars, PSI, Pascals (very rarely)
Weight:
pounds, tons, gallons
Everything uses a random unit. It's a mess but it works, and I suppose that's why it's stuck around.