There is nothing to suggest he wants to rid the world of magic or further the cause for magic. There is nothing to hint either way, nor has he said he wanted to. There is also nothing to suggest that any endgame involves no more magic. There is suggestion that the curse may benefit Rumple/Gold’s plans. If he created it the endgame should benefit him, right? It is like the first gunsmith in the world, making the world’s first hand gun, making it only to want to do that so he can shoot himself in the head. It is pointless right?