That is one way to look at it, but I see it as an artifical method to limit player character access to magic of different forms. From my understanding, and from what I gathered stated, sorcery, rune magic and spirit magic all come from the same source but use differnt so to speak resistors so that the raw power can be used/manipulated by mortals, who are otherwise to fragile to use it. Therefore, one should not limit the other. If you got the knowledge and the magic points IMO, go for it.