The intuitivity of an interface is not limited by it's appearance, it's limited by it's adherence to what is expected - logic, shell's logical expansion using mathematical and programming practices allows for significantly greater functionality an long-term intuitive use than Window's GUI does. Once the rules are known, a great deal more is permitted through a command line than through a graphical environment. Now, intuitivity is not really the best word for it, but that is what everyone uses to describe the predictable behaviour of an interface these days.