You use the chart. How does mm of a wire, including insulation, tell you ampacity? As I said it is easy to imagine a thick wire that can carry almost no current. You can’t pull that crap with AWG system. It tells you the single most important fact, how much current a wire can carry. There is no incentive for wire manufacturers to cheat the system since a thicker insulation wire just means more cost for them.

Which ties in nicely with the other charts. Tell me how much power you need a motor to deliver and what I have to deal with and I can tell you exactly what wires to use, it’s bending radius how thick it is etc. None of which I can do in the CE system.