First, we have been on several cruises including Princess pre-medallion. Neither of us has ever had a problem opening our cabin's door. Seems like a fix to a problem that never existed.
Second, you mentioned "many other wonderful functions" . Yet, there are numerous posts saying you do not need the medallion for all these other functions like making dinner reservations, ordring a drink, or even registering your information now that they reinstated the personalizer function.
Third, why are there so many posts reflecting frustration with using the medallion if it is such a great invention?