Oh it's not necessary to use them, but it provides a whole new experience with the game. By not having a PS2, I'm limited by what I can play. I have a massive collection though for PS ( I still have 3 games I need to actually finish playing through). Point being: Some people like characters that I consider absolutely useless. I want to figure out their style, and why they like these characters. I'm ALL about pure brawn and healing. I'd like to see what the real benefits are of using the other types of characters.