They stopped using them on construction sites specifically for that reason. You can just cut them off (or knock them off the wall), and open them at your leisure. Everyone hides the keys instead now.
Also, its just a stupid solution for AirBNB too, since anyone can easily clone the keys. You're better off installing a lock that accepts pin numbers and you can change whenever a guest leaves
The point is you can have both security and usability
If the guest loses the key too, it's not an issue
I suspect people mainly use the lockboxes only because other people do