Locking an app with Face ID or Touch ID is one of Apple's most powerful security features. It ensures that only you can access a particular app—whether you're handing your iPhone or iPad to a friend or if it falls into the wrong hands and someone manages to obtain your passcode.
Unfortunately, this level of protection doesn't extend to Progressive Web Apps (PWAs). Whether built with Progressier or any other PWA framework, Home Screen Web Apps currently cannot be secured using Face ID or Touch ID.