Lenovo tried that...
In the God awful T/X/P*40 days.
The worst of it was that the whole pad moved when you clicked. Which almost always resulted in the pointer moving just before the click was registered.
I did wonder at first why they shipped them all with a Lenovo mouse....after a week I'd have cursed them more if it didn't.
That being said, the trackpad on the wife's Asus is good without the physical buttons but then it does also double up as a second screen with a few party tricks so there's that.