A 1325 Dispute
You don't need to know the spell. It only needs to be on your class spell list in order to activate a wand or staff without a check. As I said before, using the emulate class feature option to emulate a a class's spellcasting ability would treat you as having their spell list with a DC of 20 (giving you an effective caster level of 0). You would be able to activate a wand or staff, with the same DC as activating a wand or staff normally.
Is there really any reason that I could not use that option in lieu of the "Use a Wand" option, besides the fact that the "Use a Wand" option exists?