The temporary, time-bound restriction is really meant to stop the user from using the app beyond a certain amount of time--App Limits setting (e.g., too much Facebook, Instagram, etc.)--or during certain times--Downtime setting (e.g., dinner time, bedtime, etc.) and not really for securing the app against usage/acess by unauthorized persons. Hence, Screen Time. Then again, the Content and Privacy Restrictions setting--which goes beyond limiting screen time--was lumped under Screen Time, so it can be a cause for confusion.