Better device protection
Phone theft is still the biggest threat to your costly smartphones. Android 5.1 has a new device protection feature that prevents a thief from factory-resetting the phone without the password for the Google profile used previously on the device. It will be difficult for thieves to replace your account as a primary account which will make the device useless for them.
The feature seems to be pretty restricted with only available on the Nexus 6, Nexus 9, and new Android 5.1 devices.
