Also, I hope this isn't delete fodder, but...
I like the idea of metric, I use it whenever I can, my weather app is in Celsius, all my tape measures are both US/Metric
But for some reason, whenever it's time for wood-y stuff, I go back to inches. No excuse on file.
Plywood doesn't care how you measure it, but starting an 8020 collection could be a lifestyle decision.