What is the purpose of closets?

I am having a hard time correlating what I see in the Wiki and what I'm seeing in the game itself.

According to the wiki...

Sometimes closets are generated without doors leading to them. The only way to get to these is for a corridor to be generated adjacent to them, or to teleport or dig in. Such closets always have a scroll of teleportation inside, and a potion of object detection will reveal its presence. Every closet has either a door or a scroll of teleportation.

However, I have come across many, many closets, and I have never seen anything inside them. At one point I teleported to the vault, but that was just on a random pathway. Am I missing something?

You generally won't come across the closets without doors unless you're using magic mapping or objection detection. Occasionally they actually overlap with a normal corridor, leaving the scroll of teleportation lying in the corridor. I've never seen a vault teleport in a normal corridor but if you've run into one then I suppose it's possible.

There's no particular purpose to empty closets, although they do make a good place to lock yourself in to heal or wait out hallucinations.