That’s interesting about the mm. Most carpenters (having been one) will measure to the 1/16th of inch, rather than the 1/8th. If you’re cutting trim, sometimes you need a bit more precision. There’s a lingo for that, “11 and 5/16 plus a c* hair.” I suppose metric could be useful to move the job site towards political correctness...

For what it’s worth, 1/16” is also about a saw kerf. But in my experience, that doesn’t really matter because, as I was taught, you don’t take the line, but keep the blade completely on the waste side.