Okay, well it's more like it taps a spot on the iPhone. Still, it's a nice way to rack up the points in Coin Dozer (free on the App Store). There isn't much to the game outside of dropping coins. It seems to work for the fellow who built this little contraption.
Then of course, you could ask why you'd want to remove the interactivity from something interactive like a game. We couldn't tell you, but we're sure that the person who built it had a fun time creating the machine.
It's not as complex as the robot this guy built, but it's probably a lot easier to make.