The defacto standard is to put nothing in an enclosing namespace unless it's needed there. The purpose of functions (especially in a language like JS) is to wrap up everything that's needed to accomplish a given task and leave no mess behind.

Then why oh why are variables global by default? (this is not meant as an attack on your point, I fully agree, I just find this awfully frustrating about JS. Sane languages have scoped by default and a global keyword, not the other way around)

You'd have to ask its designer. Sloppy programmers do like globals and JS was targeted for them.