Passcodes ensure your device is secure in case any unauthorized individual gains access to it. That's good and all but sometimes when you're home and out of harms reach you don't need or want to input your passcode every time you unlock your device.
SmartPass makes this first world problem easier to manage by intelligently removing the passcode entry requirement under certain situations. Quickly add wifi networks and bluetooth devices to a whitelist to have your device unlock without a password when they are connected.
SmartPass can be configured from the settings app.