The things is; for some games, wikis are not that good~ They aren't always well written or completely informative, or convenient.
Also, there is a MASSIVE difference between knowledge and execution. For instance, I can re-read all the details and combos for a character I want, but even after hours of training model, more hours of challenge mode, and finally even more hours of Arcade mode, I still can't do anything more than Lambda's Basic DDDDDDDDDDDDDDDDDDDDDDDD combos, and spamming C and Cavalier in the corner.