Yes I routinely use the metric system. Did you notice I said 12.5mm = 0.5". Kind of answers your question, doesn't it?
And I routinely work in numbers like 0.01mm (and smaller).
I know how large a mm. I have a drawer full of metrology equipment for measuring down to 0.002 mm accuracy.
I get it. You like large watches.
I don't.
No offense.
But the difference between 12.5 and 10.5 is HUGE! 12.5 is 19% larger than 10.5.
And don't tell me you can't visible see the difference, because I know you can. And you can definitely feel it.
But the apple watch isn't just too dang thick, but the bezel size is huge. Even the "smaller" 1.5" screen has too large a bezel.
No, I don't like thick watches.
I like watches of all kinds.
Rolex submariner is same thickness and it is one of the most popular sport watches.
Only dress watches are thinner than 10mm.