I can think of two main reasons for a phone chess clock. 1. To paraphrase what is said about cameras, the best chess clock is the one that you have with you. P

I can think of two main reasons for a phone chess clock. 1. To paraphrase what is said about cameras, the best chess clock is the one that you have with you. People usually have their phone with them, so should the need arise to have a chess clock they are covered. Not many people want to always carry a physical chess clock around just in case the opportunity to play chess arises. 2. It is cheap or free. The phone is expensive but people are going to have that anyway so that doesn't count. A decent chess clock from a known company will probably run you are least $30. For people whose main reason for a phone clock is #2 and would not have a problem with having to carry something with them I've always thought it would be interesting to make some sort of holder that you can put a phone in when using it as a chess clock. The holder could hold the phone at a better viewing angle, and could incorporate some sort of rocker mechanism so that the phone tilts slightly to one side or the other. The app on the phone could sense which side the tilt is toward and use that to know which clock should be running. (The app could also correct the display for the tilt so the display remains level despite the clock body being tilted). When you move instead of having to hit something on the touch screen you'd hit your side of the top of the holder to flip the tilt.