Operating large amount of keys with all your fingers to compose and invoke complex commands is a powerful idea - especially given that people can and do learn to navigate complex systems this way intuitively, in the same way drivers eventually internalize the interface and stop thinking about it.
Having those buttons labeled with letters in a particular layout - that's not where the power of this input method comes from. Perhaps it was a necessary Schelling point, though - QWERTY keyboard is a good default. Without it, computer vendors would be tempted to experiment with their input panels, get creative with controls, making them effectively unique per model.