You do you boo but Metrics fucking awesome. It’s simple, conversions are super easy, etc. it’s just basic numbers. You can thoughtlessly multiply or divide (assuming you could thoughtlessly do that before).
You want a real shite headache? Try translating tenths of inches. I’d just burn the blueprints and tell them to try again.
The most common place to find .1" is on micrometers. And that’s just fine until you need to switch it back to imperial or metric for the next processing…which the rest of your tooling is in.
.1" is roughly 2.54mm
.1", fractionally is ~7/64
7/64 is roughly 2.77mm
See how this is recipe for disaster?