The Pixel 4 has Face Unlock and Face Unlock alone as a biometric security option. It works pretty well as a face-scanning feature, I just wish Google had kept a fingerprint reader as an option, mostly because there are like 2.5 apps that support Face Unlock for login purposes. Today, Box has added support, bringing the total count for Pixel 4 Face Unlock apps to 3.75.
There isn’t much else to say here. Box is a storage app and you can now log into it with your face on a Pixel 4.
To find the setting, open Box, tap on your account profile (top right corner), and then scroll down to the Security section. If updated, you should see an “Allow biometric unlock” option that will enable Face Unlock.