I get a kick out of the metrics used in the UK. Candy by the grams, petrol by liters, mountain heights by meters, and speed limits in standard miles per hour....... ??
The arguments pro and con suggest we can only use one system, why? We all have a phone in our pocket which can do conversions instantly these days.
1760 yards per mile - not from my phone but from my own memory, not sure why it is stuck in there.
Addendum: I recently spent 15 days in the Highlands in Scotland, and was discussing the use of the Metric system for all measurements in the UK EXCEPT speed limit signs and road distances, and my Scottish guide said the reason was financial - that when the government highway officials finally came up with a cost for a whole new set of road signs all across the UK, they, the public, balked at the cost, and decided to stick with their existing Imperial measurements for roadway signs. I don't know if this is true, but it sounds like it might well be.