I have two different appliances that have them, and the lack of tactile feedback is really irritating, especially when a button press doesn't result in instant visual/audio feedback from the device. (Makes you wonder whether or not you actually activated the button.)
I strongly suggest using actual buttons.
Sometimes I'm absentmindedly staring at the screen trying to click the desk, because it feels almost the same as the trackpad now.
Tactile feedback is very important!