"pointing at the screen" can be done a lot better, a number of different ways. My personal favorite is the Trackpoint, IBM's nifty little nipple that lets you use a joystick from the home row. You can actually type while using your mouse, and it's a a very jarring experience. Barring that, a touchscreen is also a great interface for quickly interacting with specific UI elements. I like Apple's trackpads, but the rest of their input peripherals are pretty terrible for ergonomics.