Ralisticallly, what they are saying is "we want base-10." Base 10 makes doing all of the little calculations we have to perform in our heads every single day far easier and much less annoying. It's pretty much objectively better, though how much so is quite subjective.So really, whenever anyone says "we want metric!" what they mean is "we want new signs!"
I think that's what they think they want. What calculations are those, though? Cook in metric and suddenly you're dividing by a thousand all the time. Dealing with distances? 100km or 62 miles, doesn't matter. How often do we think in yards? When we are, aren't we usually converting to feet or inches? In which case we're dividing by three, or that multiple of three, twelve. Really we want base 10 because we have ten fingers. Base 12 is much easier to work with when you're doing the math in your head because it's so much more divisible. Yeah, if you're doing big calcs Metric all the way... but weren't we just arguing on here a few days ago about how useless Algebra is to most people?