Well, the real advantage is the button can change or you can add more buttons trivially. Compare the on-screen dialer and keyboard of the iPhone to the old scho

Well, the real advantage is the button can change or you can add more buttons trivially. Compare the on-screen dialer and keyboard of the iPhone to the old school 9-digit keypad. The former is superior for most use cases. Also you can abstract away your GUI interface with a hardware button if preferred. I'm using a hardware keyboard to type this for example, even though this computer has a touch screen. I have this flexibility and customization options that the old school approach didn't really have.