The problem is taking the millimetre as the base unit for measurement. It's far too small; the cm would have been better.
My point entirely - but it's not an SI unit, so it becomes confusing.
So, as I said, logical but useless.
The base unit is the metre - so far so good, but it all falls apart after that. That's why the millimetre is so prevalent, especially in construction, because it's a thousandth of a metre - right and proper but not much good from a practical point of view.
However, we used metres and millimetres for many years, and it's only when you move outside construction that the frightening centimetre raises its ugly head - trying to envisage things with that description just doesn't work for me, I have to go back to millimetres.
