Well, let's chime in with this angle...
The units being measured (miles, km, feet, whatever) are actually pretty arbitrary. Cubits? why not. The higher order question is "what are you doing with it and what precision is required?"
So this thread gets into precision, which I do find interesting. But IRL, I find that most situations rarely benefit from more than 4 significant digits, usually 3 will do and 2 is often good enough for decision making.
If I had ridden 36 miles, does 36.4 matter?
If I did a season of 3000 miles, would 30 matter? would 3?
I can find you both cases in finance, where the way we need to work sometimes says "need it to the penny," other times we round to the nearest million.
So, what I'm asking this thread is : "what level of precision is _useful_?" and when does a lack of precision become troublesome?