How useful are map and set objects?

Question

I don't really see how they could be useful, maybe I'm missing something, what exactly are they supposed to help you with? So far, all I really need in projects I make are normal arrays and objects

Answer 1

A map is like a dictionary or look up table.

Answer 2

Map can be very useful at least by two reasons: 1 - the keys in a map can be of any type, not only strings, as in objects. 2- a map is an iterable.