yeah, but they do nothing to stop a locksmith in a fugue state from rekeying all the bolts to match the neighboring property and vice-versa, and then the realtor can walk right in, and you're locked out!
so it's better to just leave the door open.
Yes it's illegal and there's a consequence but do you care about it after you've been robbed?
You could say the same with a lock. Do you care once it’s broken?
The point of a lock is that it's something to break. That takes skill and visible equipment. The more skill yoo require the more likely the smart guy would do better things to earn money than crime. the more visible equipment the easier it is to track.
You’re proving the other persons point - the reason why the a thief doesn’t trivially pick locks isn’t because of the lock, it’s because it’s illegal and there’s a consequence.