The Pixel 7 finally reintroduces Google's face unlock feature, which originally debuted in the Pixel 4 smartphone. But you'll still want to use the fingerprint sensor on your Pixel 7, as face unlock doesn't work with Google Pay or app sign-ins.This limitation was first noticed by Max Weinbach, a journalist and contributor to 9to5Google. Shortly after the Pixel 7 launch, Weinbach tweeted that his Pixel 7 Pro automatically declines all contactless payments.Evidently, Weinbach encountered this problem because he tried to activate Google Pay with face unlock. As explained by Mishaal Rahman of Esper, face unlock is a "Class 1" biometric system, meaning that it isn't secure enough to unlock Google Pay or sign into apps.

An official statement from Google, which was obtained by CaschysBlog's Felix Frank, provides further clarification. "For secure activities like app sign-in and making payments on Pixel 7 or Pixel 7 Pro, you can use Fingerprint Unlock or rely on a strong pin or password."

We aren't exactly surprised by these limitations. Unlike the Face ID system on iOS, which uses lasers to measure the depth of your face, Android's face unlock doesn't utilize depth sensors or any other fancy technology. It simply scans a 2D image of your face. (Samsung is the exception here, as it combines face unlock with iris scanning.)

Related: Google's New Pixel 7 Pro Has the "Pixel Curse"

Technically speaking, the Pixel 7 is better equipped for face unlock than previous Android phones. Machine learning algorithms and the new autofocus selfie lens should offer an increased level of security. But I doubt that Google will upgrade the Pixel 7's face unlock beyond a "Class 1" system.

We're currently working on our Pixel 7 and Pixel 7 Pro reviews. And we're excited to share how we feel about the new face unlock system, along with all the other upgrades included in these phones. Join our free newsletter to read our reviews as they drop.

Source: Max Weinbach, Mishaal Rahman