To protect from pickpockets and other thieves.
A “beacon” that you wear on your person that your smartphone can detect. You can turn on the theft protection, and when your phone is taken a certain distance from the “beacon,” it sounds a loud alarm (even if the phone is set to silent mode and the volume is down.) When you put the phone down (at your office for instance), you can switch to motion mode, and the phone will sound the alarm when moved and not when you’re away.