Why use pointers?

Hey all, teaching myself CPP through a few books (and a little bit of CS in general through CS50) and hit a road block.

I understand what pointers are, and understand they’re a big part of programming. My question is why?

What do you use pointers for? Why is forwarding to a new memory address preferable to just changing the variable/replacing what’s already at the memory address or at a new one? Is it because new data could exceed the size of that address already allocated?

Thanks in advance!