I would implement AP and other costs for usable items. There are plenty of other features that require an AP/EP cost (i.e creature sacrifice, friend removal, searching for specific dates in the calender, mood panel posting and a few other things I can't think of at the moment.) It makes sense in my opinion to add costs to usable items like Pass Papers, Harvesting tools, kill/revival items, dice, cauldrons and legislators.
Just to clarify, I'm not suggesting this as a deterent for resource depletion.I just think its odd that they don't have cost to use when they have clear benefits to the user.