With "canon type", we were trying to describe the media format of the canon rather than its literary genre, except that RPF isn't really a media format, so we couldn't call it that. (I guess we could call it "Fandoms by Canon Format" instead. I don't know if that is clearer.)

Technically, yes, graphic novels are books and animation can be TV or film, but these titles would quickly overwhelm the categories and make them less useful for people looking for book fandoms or live-action tv fandoms. Basically, I don't there is a perfect solution.