Nim isn't the only language to define `Natural` and `Positive` in this way. Ada does the same thing, and that's the language people reputedly use to fly airplanes and run the train system. So the Nim devs can't be _entirely_ on the wrong track (no pun intended).
I guess your complaint is that `age` should not be of type `Natural`. That probably depends on what's needed in the application. Lots of people only ever display a natural number for their age.
