Another reason worth mentioning, I think, is: trying to open doors or boxes involves not only "power" but strategy. I just opened three boxes in a room after killing a demon (in Castle upstairs, as I recall) and found three bad results: one box contained a trap that alerted all the Castle residents to attack my group; another contained poison; the third contained a rain of fire.
Had to fight and kill a demon to get dumped on. Fortunately, I had learned enough strategy by this time that I simply reverted to the save made just prior and thus escaped all injury.
Jeff is teaching us all to learn strategies for survival. (At least in Avernum 4 and other such games.)