As noted by the folks over at 9to5Mac, a new system sign-in view in tvOS 15 provides users with a consistent sign-in experience across all applications, while also making it easier for users to sign in to tvOS apps using Touch ID and Face ID on their iPhones.
The new sign-in screen on tvOS 15 displays a “Sign in with Apple Device” option. When users pick this choice, a notification is sent to their nearby iPhone or iPad.
This notification uses your iCloud Keychain information to automatically suggest the correct log-in information. So for example, if you’re trying to sign in to Netflix on your Apple TV, the notification will automatically choose your Netflix log-in details.
“In tvOS 14 and iOS 14, the Apple TV remote attempts to streamline the tvOS sign-in process to a degree, but this new feature in iOS 15 and tvOS 15 takes the experience to the next level. The intelligent notification presents the necessary log-in information and requires a simple biometric authentication before sending the details to your Apple TV.“
This new tvOS 15 feature also works for authorizing purchases made using the Apple TV.