Right, you can't use them, but you can generate them right? With that and the apparant lowering of the AI's tech pace, and isolated start can peacefully expand, consolidate, and build defenses, all while generating EPs for when they meet another civ. Then once Caravels come around, or you run into other civs on your landmass you have a whole bunch to immediately start wreaking havoc on your rivals. Also, in order for another civ to stop espionage, don't they have to dedicate points towards whichever civ is spying on them? If so, a lead in EPs upon meeting of a civ would increase your chances of actually doing something to your rivals, because they probably haven't been creating EPs as well as you have. And, you might even have some Great Spies hanging around with nothing to do...