[TraspSE]

You're missing the point. What I'm saying is that the metric system is built around base 10, not because of its properties, but because it's the base we use in general - and the simplicity of having one single system with seamless conversions.

Arguing in favour of base 12 systems would make sense if it seemed doable to introduce more numerals and replace base 10 altogether, in my opinion, but that's not realistic.

Besides, if you live somewhere where the metric system is used, and you're unable to manually measure and cut one third of a meter (0.333m/33.3cm/333mm/333333µm) with the same speed and precision as you would be able to using a yard-stick - then you probably shouldn't be allowed near the tools needed in the first place.

PS. In practice, the boss would've asked you for a piece that is either 3dm, 33cm or 333mm long, indicating the expected precision.