As a Canadian, you learn both systems. Metric is obviously far easier and more logical - I don’t think anyone really questions that, do they? Ask any scientist or military commander, US or otherwise.
However, usage trumps everything else. In Canada, we use metric for anything official, but we still cling to imperial for certain day to day reckonings, particularly height and weight on a personal scale. So even though I am fluent in metric I still think of my height in feet and inches, for example, and my weight in pounds. And I have English friends who still think of their weight in stone.
For D&D imperial feels better to me because it’s more old-timey, but I might switch to metric when RPing a gnome or something. Occasionally I have to do a bit of math in my head (eg how far is 60 metres in feet?) but it’s not much of an inconvenience. Except temperature - I just stick with Celsius because Fahrenheit totally confuses me (water freezes at zero degrees, dammit)!
The units chosen make no difference to what game I choose to play.