Biometrics to Sign In to Mobile Application

If one could use their mobile phone biometrics features (Apple Touch ID or Face ID, for instance), signing into and out of the mobile app would be much faster. For instance, I log out of the application on my mobile device when I'm at my desk so that the mobile app and desktop app don't ring at the same time. When I'm away from my desk, I sign back into the mobile app so that I can receive calls when I'm on the go.