ALL measurements, standards, units, etc, etc, including the metric, are arbitrary. What is a Meter after all ? Well, what I remember from school in Mexico, the Meter is derived from one 10th millionth of the distance between the equator and the north pole. Because the earth IS NOT perfectly round, if the measurement had been from the equator to the south pole, it would have been slightly different. The Kilo was arbitrary also. Dividing or multiplying by 10 is what makes the system more rational and simpler. One of the few things the French have done right in the last 200 years. But then the entire world still use in navigation standards from antiquity. Why is a circle divided in 360 degrees ? Well, the greeks and the Phoenicians used it that way. Astronomers use AUs for distance. That's the size of our solar system. What if they had used some other standard ? So the US still uses for everyday life a standard which evolved in the middles ages in Britain and we don't go along with the rest of the world. So what ? Big deal. As long as we don't forcibly impose it on the rest of the world, so what ? Besides, as I stated earlier, our scientists, engineers and manufacturers have changed to metric in order to export or negotiate with the rest of the world and Americans use the metric system a lot more than they realize or outsiders give us credit.