Sometimes you need precision, sometimes you need accuracy, and sometimes you need both. For completeness I'll say that sometimes you need neither, perhaps politicians know more about this last part. Using Imperial measures makes this clear - do you really need to know how big your field is to the millimetre? To the centimetre? A foot will do.
My foot is, strangely (there's that British sarcasm again), a foot long. I can go into a field without tools and measure using my feet and be quite accurate.
I programmed Ruby for years and it was always said that it was designed to work for the human over the computer, Imperial is much the same, as were the things like pre-decimal currency (I don't want 12 eggs, can you sell me one? Easy when I've 240d to divide into, not so easy with 100 pence).
Use what's appropriate, don't wed yourself to decimal.