The reward is one-click sign-in for 500M users. If you're an instant personalization partner, zero-click sign-in for 500M users. To have zero-or-one-click sig

The reward is one-click sign-in for 500M users. If you're an instant personalization partner, zero-click sign-in for 500M users. To have zero-or-one-click sign-in for half a billion users is a useful feature to have. Just keep your own login system if all else fails.