Android introduced face unlocking in 2011[0]. It used the regular front camera and hence had no depth information, which makes it vulnerable to photos[1]. It was removed in Android 10, when a new face authentication interface[2] was added. Face unlocking without specialized hardware such as what iPhones have is not secure.
[0] https://www.androidauthority.com/face-unlock-android-4-0-ice...
[1] https://www.androidauthority.com/android-jelly-bean-face-unl...
[2] https://source.android.com/docs/security/features/biometric/...