Because you are thinking about a single door. Cost of implementing and maintaining non-copiable RFID is much higher. My workplace uses Medeco M3, I have 7+ keys

Because you are thinking about a single door. Cost of implementing and maintaining non-copiable RFID is much higher. My workplace uses Medeco M3, I have 7+ keys for the various areas I have access to, I can be given a key for a specific area for the time I need to do something over there, etc. Some areas behind electronic access as well but it is rudimentary and it did cost us an insane amount of money to just install that an a few doors because we have to use union shops that abuse us (took them weeks to do, four people showing up to find out they were missing a plate so they came back a week after and found out another part was missing etc for 3 months, no kidding...)