When enabled, PAM services will be configured to use fprintd for authorization. Enabling this option will add fingerprint-based authorization to all PAM services, including those which can authorize users in the background. If this is undesired, you can override this setting on a per-service basis through config.security.pam.services.<name>.fprintAuth. See https://github.com/NixOS/nixpkgs/issues/442117

config.services.fprintd.enable