Control4, one of the lower-priced home automation solutions, already has apps for your iPhone, Android, iPad and laptops to control your house, so why do they need a touchscreen for the wall? Because it's always on.
Those mobile phone and web-based solutions are fine, but you run into the issue of having to open up the app or click on a bookmark in order to load the control scheme - kind of a hassle if all you want to do is turn off the light downstairs. With the in-wall touchscreens, they're always active to the Control4 home screen and lets you quickly (and capacitively) control your house.
The InfinityEdge touchscreens are $US500 and $US900 for the 5-inch and 7-inch, respectively, and can be powered by AC or Ethernet, and be wired or wireless. Like the rest of Control4's stuff, you need to use a dealer to install them.
I'm currently testing out a Control4 setup now, so a review will be coming soon. [Control4]