It's not nonsense when it's running the 7.3.5 client - even in the Blizzcon demo the dungeon finder was still there. There's elements of newer WoW that they've obviously left in. Maybe they'll re-add that interface, who knows - maybe it is a bug, maybe it's intentional. I'm taking it as it's not a bug, as it's the 7.3.5 client running 1.12 data - based on the fact that all of the interface options aren't as they were in 1.12 and reflect the 7.3.5 client.