I have a similar concept on my Android phone however it uses the Wifi to access the LAN and talk to my MythTV's TCP control port. Works great for control and is responsive etc.

However the issue is that you can't leave the screen backlight on all the time or it will run the battery flat in some hours. So when the screen goes off, it locks the screen which means each time you pick it up you have to unlock it. I guess you could disable the lock screen temporarily or it might be an old device you are using.

Would probably be OK for one off events such as setting an air conditioner on or bringing down a motorised screen. Or maybe just the "off" and "on" processes of your system. You'd then use the regular remotes. Kind of half baked then.

The other issue is the touch screen is not so easy to hit the right buttons when you're looking at the TV. This is where you kind of need physical buttons to help guide your fingers. Even with quite large soft buttons on the screen your fingers can get lost if you aren't looking particularly if you need to change buttons.

I'd probably say get a Logitech, URC or Philips type universal remote. They can be quite cheap and are quite powerful.