Who says one has to use fractions with one unit and real numbers with another? Both units are just a different multiplier. What stops one from using 3/16th of

Who says one has to use fractions with one unit and real numbers with another? Both units are just a different multiplier. What stops one from using 3/16th of a meter? (I admit I rarely see SI units with fractions, but if one finds them so useful, why not? Personally I prefer non-fractions by the way, it's much easier to rank and compare numbers in your head if they're all given as real numbers. E.g. can you tell quickly if 5/17 is bigger or smaller than 8/30?) And how will you square 2.829 inch? Not everything you measure will happen to be some perfect fraction