With a touch screen, there is no physical feedback until you touch the screen, and that feedback is "you've touched a screen."
With a button, even if you look once to confirm its location, there's physical feedback of "you're touching the button and not the edge between two buttons", "you've depressed the button" and "you've released the button".
The difference in physical feedback means the difference between looking and watching - and the time required to watch your finger interact with a virtual button and verifying that the interaction was registered.
With a button, even if you look once to confirm its location, there's physical feedback of "you're touching the button and not the edge between two buttons", "you've depressed the button" and "you've released the button".
The difference in physical feedback means the difference between looking and watching - and the time required to watch your finger interact with a virtual button and verifying that the interaction was registered.