iPhone FaceID concerns

Apple Support

Optic ID, Face ID, Touch ID, passcodes, and passwords

To use Optic ID, Face ID, or Touch ID on supported Apple devices, the user needs to set up their device so that a passcode or password is required to unlock it.

It’s honestly just gonna be a numbers game until they make a phone that pinpricks your finger and analyzes your DNA, lol. Apple says 1:10k vs 1:1MM for Touch/Face, so it’s def a step up for the threat model of a random passerby grabbing your phone. But if you are roommates with a doppelgänger, then you may have to adjust your threat model.

As a data point for your actual question though, yah, I think a vast majority of iOS users do use it. It’s definitely convenient if you like longer passcodes, Private in the sense that it’s supposed to only happen on a local separate chip, and Secure enough for a vast majority of use cases.

If it’s Security you’re really worried about, enable it and pass it around to all of your friends and coworkers for a month to make yourself more comfortable with it.

EDIT: Oh, I should also mention that it has Attention-Aware features for if your eyes are closed or if you’re looking at the tv, so just another useful layer.