Ok, not really functional

You cant display the time on the calculator display face, so you cant really use it as a watch face, and the buttons on screen are too small (and have no touch zoom feature for example such as the iphone screen keyboard).
The face doesnt really look like you are wearing a casio, it looks like you are displaying a smaller picture of one on your phone face.

Uvmhobo about Geek Watch - Retro Calculator Watch