You are a bit
My father is disabled and for a time had a care worker visit twice a day. The idea behind these was that a spare key to the front door was kept in a metal box with a combination lock bolted to the wall near the door.
The care agency have the code to the box so if they arrive and the door is locked, rather than waiting for the occupant to make their way to the door to unlock it (or if there has been an accident or fall and the resident can't get to the door), the care worker can just let themselves in and you (theoretically) don't have the security risk of handing over your door key to an agency.
Plus, if there is more than one care worker who visits (as they work shifts it may be a different person at different times of the day), you don't need to give each one a key, they just all have a copy of the box code.