The more restricted and limited you make something, the easier it is to use.
Remove options, reduce flexibility and the device becomes simpler and easier. Good for the novice, bad for everybody else.
The real trick is to gradually surface functionality: provide powerful abstractions & flexible conceptual tools, but then hide them so that they only surface when they are needed, and, more importantly, when the user is able to cope with them.
So, by all means hide files, and other abstractions that serve to complicate the interaction & confuse the novice, but keep them in the background, waiting until they are needed; and provide neat ways of discovering and learning the conceptual tools required to use our devices to their full potential.
User interface design is about planning the user's learning process; guiding them on their journey from novice to expert.