Apple has actually combined the two with their touchpads. When you press on them you get the "click" feedback. But its not actually a physical travel that activates, it's what they call "the haptic engine" that vibrates in a way that makes it feel like you've clicked a physical button. It works really well.
However, I think that such buttons are far more expensive than a physically activated button, even if the latter is engineered to last a lifetime of heavy use.
