Like Plunkingtom said it simulates a Battery Pull. And basically that is like rebooting your PC. If you start to get low on device memory (Not your media card) your phone will slow down and start to run sluggish.
If you normally want to reboot your phone, you have to open the back of your phone and pull out the battery while the phone is on. This will reboot the phone and will free up the used memory and make the phone run faster.
If you want to bypass the battery pull and use quick pull, it will save you the wear and tear on the back of your phone.
As I said, it SIMULATES a battery pull and like everything else that is simulated, it isn't the exact same thing. But it does help.
