I played like that with a friend of mine, she's a member of this forum too actually. Ezellwen. She had only played FFVIII and the first half of FFVII. So then we decided to try out FFIX, her playing and me watching, as I had already completed the game. Which is fine, I'm one of the people who enjoy watching other people play games, but it can get pretty boring to watch other people fight random encounters over and over again, so this 2 player in battle was a good way to make that more fun. She only plays FF's for the story and side-quests too, so it was more fun for her too not having to battle by herself all the time.