There's really only one unit for length: the meter. Centimeters aren't a different unit, they're "hundredths of a meter".
You can call your lengths of timber "frobs" if you want, even in public! You could have people order them that way and sell them that way. The only requirement most places have is that you also specify what that is in meters so that people who don't know what a frob is, know what they're buying.
It just makes sense that your frobs should be a useful number of meters so that they can be divided or handled easily and don't require 15 decimal places to express.
Edit: I have a question for you: would you support changing your currency away from 100 cents to the Dollar to something like the old Pound with 240 pennies to the Pound?
After all, if you're talking about measurements everyone uses and need to divide up, it's far more commonly required for cash in people's everyday lives than length or volume or anything else!