Like Mohawk said, opening locked or otherwise impassible doors is the main purpose of that part of the spell. I believe the wording was originally more useful in the prototype version of the game. In the British TV commercial, the
Fire of Wrath spell was differently worded:
This spell may be cast on any
object or door in the same Room
or Passage. The object and
anything in it will then be
destroyed. The spell may not be
cast on Monsters or Players.
This indicates a need to not only open but also destroy a door, probably due to it being locked or otherwise impassible. Personally, I'd have liked to have seen this application to objects to extend to opening chests and furniture in the Genie spell we use today. Maybe this universal opening feature would make a good seperate spell for a scroll, instead.
There are some possible reasons for casting a Genie spell to open a door in the Main Game System Quests, Kellar's Keep, and Return of the Witch Lord (there's probably more reasons in the other expansions):
- In Castle of Mystery, Quest 10 of of the MGS, the spell may be cast to reveal where a Hero will teleport. The next Hero through the door needn't immediately roll two red dice, the spell did that for him. That foreknowlege allows a choice as to who enters that revealed location through the door.
- In The Great Citadel, Quest 6 of KK, the spell may open the locked door at location A without needing to roll under a Hero's starting Body Points on two red dice.
- In The Eastern Passage, Quest 7 of KK, the spell doesn't open the door at location B. It should, as the door that doesn't budge is guarded by no less than 8 consecutive traps. Originally, this door allowed access to The East Gate (Quest 9) in the EU version. OK, the Parchment text says the wooden door must be exited, but still--talk about a red herring!
- In The East Gate, Quest 9 of KK, it may actually be necessary to cast the spell to open a door or the Quest is failed. The reason is a Hero may have had his Mind Points previously reduced to 1 by a Chaos Warlock. As any Hero but the Dwarf must roll equal to or less than his current Mind Points on two red dice to pass through the door at location D, it can be impossible for a Hero with 1 Mind Point to pass. Only a Genie may open the door for this Hero and prevent the failure of the Quest. Unfortunately, it is likely the spell was already cast...
- In The Cold Halls, Quest 2 of RotWL, the spell may be cast in the revolving room to reveal a chosen room without rolling a random die. A Hero must still roll to exit the revolving room, however.
- In Halls of the Dead, Quest 6 of RotWL, it is possible for the Dwarf and Wizard to get into trouble before freeing the Barbarian and the Elf. As a last ditch effort, the Wizard could cast a Genie spell from anywhere on the board to open the door to the central chamber, thus allowing the Bariarian and Elf to be placed and take turns.
- In The Forgotten Legion, Quest 7 of RotWL, the spell may be cast to open the opposite door at B from the relative safety of the bottleneck corridor outside of the room. This provides the safest way to deal with the 3 to 1 odds of the central chamber.