What is the purpose of pointers and address ? Why should I use them and what are they useful for ?

Answer 1

https://stackoverflow.com/questions/162941/why-use-pointers

https://www.quora.com/Why-do-we-need-pointers-in-a-C-program

Answer 2

Pointers are variables that store other variables memory addresses. They allow you work with data on the heap,control how memory is allocated plus you can use them to access low level software like Operating systems or control hardware. They are fun and really powerful features.
You can read more about them online.