That's a neat idea, but it doesn't cover the issue of knowing what those spells do. I probably should have clarified earlier, but most of us are not familiar enough with all the spells in the game to remember all of their functions, durations, casting times, ranges, component requirements, and so on, so we need a way to track our spells AND be able to efficiently look up or record their effects and spell specifics (short of writing every single one down by hand, which would be extra murderous for divine casters).