[pests]

To try to answer your first question, coming form someone who is also not an expert in Haskell or monads.

"apply a function to a box directly; no need to perform all the steps ourselves."

The box doesn't change, and it also doesn't matter what's inside of it. You are attaching the function to the box, who later knows how to apply it to itself. If you were to open the box, you would need to know how to handle all the possible contents. It's key here that you are only handling a box and nothing else.