Morgan Freeberg left this notion hanging around:
The metric system is all about preening. “Ooh, look at me!! I designed a starship, and to show how advanced it is I’m measuring the hull length in METERS!!” Silly. The meter is just as arbitrary as the yard, which is rumored to have been the distance between King Henry I (Beauclerc)’s nose to his thumb with his arm extended. The meter is 1/10,000th the distance between the equator and the North Pole. So it divides by ten, big whoop, it’s still arbitrary.
How you going to cut a 1m board into three equal pieces? Metric is for multiplying, imperial is for dividing. When you’re REALLY building something, it’s much more commonplace you need to divide. Metric system sucks.
The meter has since been redefined — it’s now based on the speed of light, which is probably less changeable than the size of the planet — but it’s still kinda clunky: how far that light travels in 1/299792458 second. (Especially when you consider the definition of a second: the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.) By comparison, King Henry’s arm seems almost, um, real.