[Haskell-beginners] Lens and imperative programming

Hi, I'm reading about the Lens package, and I'm scared by the imperative style that it enables. I know the limits of imperative programming, and despite the fact that lens are purely functional by themself, I'm scared about limits in readability of code. I'm afraid of writing "write-only" code. I guess I'm wrong, but I'd like to know your opinions. Giacomo