Lol when my kids were little we had cats, and I wanted to make sure they had options to get in and out of some rooms to get a break from the kids. I made something similar with 2 small eye hooks and a 4" double ended brass snap.

Kinda defeats the object of closing your bedroom door to prevent fire/smoke spreading but I can definitely see how useful it’d be if you had dogs and cats. Or flatmates. Or family members you don’t particularly want to be naked in front of after your cat walks in and inevitably leaves the door wide open. Can you easily remove it from the outside of the room, or do you need to be inside the room to attach and remove it?