The point is really that lenses are values that represent locations in a data structure. And, as values, they can be combined, transformed, serialized, etc etc. Imagine having a type that represents a chain of method selectors, and that gives you some idea of the purpose.

The fact that method selectors only appear very rarely as first-class values in most languages means that most people aren’t tuned in to scenarios where they could be applied. But I bet you’ve invented special cases of this yourself, when you had a function that needed to dig data out of one of several locations, depending on other inputs.