I think one of the reasons our commercial culture likes all music to be fast and snappy is because in fast music it is harder to recognize the passing of time. You listen to the tunes, to the catchy phrases, but you are not allowed to feel just how time slips away. Slow music is good for contemplation but is probably terrible for business, so you don't get much of it in your daily life. One of the noble things you can do in a piece of 'serious' music is allow for an experience that can't happen in your everyday life. the passing measures is that kind of experience.