Difference between returning reference vs returning value C++

Question

Question about why is it necessary at all to return a reference from a function.

Following code behaves exactly the same, if we replace int& with

Answer 1

In this case the difference is that returning by reference allows caller to modify the data member by assigning value to it, while returning by value returns caller only a copy of the variable.

First allows you to write:

myObj.GetVal() = 100;

While the latter doesn't.

Note that the first in a way allows caller of the function to obtain a reference to a private data member and they can modify it at will. For me this is something which i like to avoid. I do not want users of my class to change the state of my class members at their will.