But that's not going to be how these watches are made. They set it to 150, which means there is almost no value in creating customised tooling just for the asse

But that's not going to be how these watches are made. They set it to 150, which means there is almost no value in creating customised tooling just for the assembly. The parts may be mass produced (and used in other products), but their tolerances in this assembly will mean they have a low yield, and expensive manual quality control. This is called batch production. It is not akin to a printer and even if it was, limiting the production quantity would, by definition, mean it is not mass produced. Finally, quantity is irrelevant to whether something is classified as art. My point was that the fact that it was created at all is meaningful and valuable.