macOS Catalina and iOS 13 might use Face ID and Touch ID to sign onto iCloud
Apple appears to be testing out a new way for users to log onto iCloud.com with its next operating systems, according to 9to5Mac. The site reports that users who have installed the beta for iOS 13, iPadOS 13, and macOS Catalina can sign onto their accounts using Face ID and Touch ID, on their devices.
Beta users who visit beta.icloud.com either on their beta-equipped device or on their desktop are greeted with a popup asking if the user would like to use either of those systems, and then proceeds to log them in, without requiring two-factor authentication. It seems as though it would be a convenient and logical step for the company, given that you can already unlock your devices and make purchases with Apple Pay using either system.