The computer keyboard is important because it is the most effective input tool for letters and characters. Computer keyboards are analogous to the keys on a typewriter. Even if the technology has the ability to create letters and symbols, the keys are necessary to tell it which ones to create.
The earliest computers have simple manual input controls. As they became more developed and the idea for a personal computer was born, it became evident that more intuitive and useful input devices would be needed. Early models of mouses and keyboards were refined through time into what has become the standard keyboard.