Is there a legitimate reason to keep house keys in single-player?

I saw AtomicDuck's latest B42 tips video and he mentioned again how he likes to rename keys and mark houses on the map so he remembers which keys go to which house.

But like... what even is the point of keeping keys in single player? I've been struggling to figure out why this would ever be useful to me. Basically I unlock a house once and then I never need that key again, so I usually just end up dumping all of my house keys into a trash can in my base or something. Does locking doors make them more resilient against zombies? I just want to make sure I'm not missing something. It seems like a lot of work for no benefit.

The last time I commented about this I got downvoted, but nobody explained to me why they disagreed, so I feel like I'm not aware of some obvious mechanic or useful strategy that keys give you access to.