In Android Pie, an API was created to allow apps to use a general form of biometrics. This means that rather than using specifically the fingerprint sensor, the user can use iris scanning or facial recognition as well. On my phone, I find using the iris scanner to be far more convenient and consistent than using the fingerprint scanner. Currently, the LastPass auto fill app only uses the fingerprint sensor. I think that LastPass should adopt this new API. As described in this blog post (
https://android-developers.googleblog.com/2018/06/better-biometrics-in-android-p.html) by Google, when implemented correctly, it is backwards compatible with older version of Android, falling back to just the fingerprint scanner. This means that users who do not have Android P will not be negatively affected. In theory, this should be a very simple feature to implement, but would go a long way in allowing users to have greater convenience.