I think this is why they have both ratings. A quality rating and a rewatchability. As the site appears to be in private beta I can't play with it directly, but I would assume both ratings are exposed when you look at a movie, which will help you decide if you want to watch it. For example, if I come home on a friday night and I want something light and enjoyable to watch, I definitely don't want to watch Primer no matter how good it is. I'd instead go for something with a high rewatchability score. But if I'm in a mood for a "truly good" film then I can go for the quality rating score and ignore rewatchability.