This app is designed just to guard your device from intrusions. It can sense proximity of an object towards the device. It can sense shaking or moving or tilting of a device.
This app need to be turned on only as it was mentioned above if you want to protect and secure your device from an intrusions in the surroundings. For instance:
When you leave your device on the table nearby.
When you leave your device plugged in a charger nearby.
When you don't want anyone to compromise with your device while you are resting nearby your device.
Using devices's sensor power, if unwanted intruder try to compromise your device, it will trigger an alert alarm sound.