Pointless rooms.

[Stolas]

Sorry for the bump, but this is a good thought provoker for me.
Even with the exploration angle,
I'd still try to give every room a purpose
beyond challenging the player with difficult navigation or adding atmosphere.
Adding items like oil and matches,
Providing a strategic path,
Adding optional story elements that expand the player's immersion,
Or a sort of trap that will add to the suspense of the game,
These are just a few ideas that can be employed
for all the extra rooms in your story.