Well, the dungeon exists strictly as a place, and to a degree, required to meet the game's goals. What purpose would a door 'just exist' for? Whatever it's doing, why it's described, must have some impact on play.
Well, here we come to the point of asking what the rules are for. In DW you're depicting adventures in dungeons. Outside of that and related stuff DW has nothing to say. In the dungeon there's no 'just succeeding' danger is everywhere. But if you want a door just for color, ok, then when a character opens it, it's just open! Does that seem to violate the rules? Yup! Because the rules are about dangerous dungeons, not potempkin dungeons filled with doors of no consequence.