If God wanted us to use the metric system, Jesus would have had 10 disciples.Why does it matter?
Looking at water. 1L = 1kg, 1000L is 1m3 and weighs 1000kg which is 1t. Water freezes at 0 and boils at 100 degrees C. 1m head pressure = 10kpaMetric system is convenient because it is a base 10 system. All calculations and conversions become simple. And with an added benefit of getting as much precision as you want without tangling yourself in conversions.
While woodworking, I often have to pull a pencil and paper to do something like : 13 7/16 + 2 1/4 + 3 7/32 - 2 15/16. This would never happen in a metric system because it would be something like : 34 + 23 + 2 - 13.
Easy to handle in your head or a simple calculator.
Liquids is similar. 1 liter = 100 centileters = 1000 mls. Its easy to figure out if I say I need 15.86 liters of whatever and you can convert it to ml. If I said, 15 3/16 gallons, you would atleast pause or more before you can tell me how many cups is 3/16 gallons.
Temperature and weight is the same.
I know its an unpopular opinion in the US and especially on an internet forum but tying a measurement system to national pride is misguided at the very least.
