It does have a biometric scanner. It's an IR-based 3D facial structure scanner. It's not camera-based facial recognition. It's directly comparable to how the fingerprint scanner works. It would just be difficult for us to support both for the planned 2-factor auth feature.
It's not really much more or less convenient. It's a bit different.
However, it's likely that we'll support 2-factor unlock with fingerprint scanners first unless it turns out that the code is easily reusable.
We want people to set a strong passphrase as the main unlock method.