if you are converting miles to 16ths of an inch you are doing something wrong.

really there isn't much need most of the time to convert between miles and inches or even feet and miles. the only real reason for that is to compress the number when you write it down. there is nothing stopping you from using deca-feet or kilo-feet.

typically when you are working in miles you aren't measuring down to the foot. so you would say something is 3.5 miles not 3 miles and 2640 feet or 3 miles and 880 yards.

the imperial system is designed around construction. using either feet or yards as our base unit for construction we can easily divide it into many different factors using inches. want something to be 1/3rd of a foot? easy that is 4 inches. now try doing that with metric.

really the imperial system (for distance) has multiple different measurement scales it just so happens that we designed them so we can easily scale between them. metric only has one. the meter with multiple prefixes we can attach to it. i will grant you that metric is far better for most scientific measurements. and when you get to relativistic speeds and stellar distances the imperial units mean nothing to me, i need to see it in metric to get a proper sense of scale.

now i am not by any means against metric, i just don't loath the imperial system.

however at relativistic speeds and stellar distances your precious metric system sort of breaks down. how many kilometers in a light year? you can use a calculator, and good luck. :P

*well i guess light year isn't really a metric unit but it is a commonly used scientific unit of measure, and does not easily convert to meters.