That article talks about butterflies in general. Most butterflies that live on the reef in the wild do so because they eat coral polyps which is why they don't really make the best inhabitants for our tanks. There are a few that are semi safe but should be kept in a reef with caution.
It will eat some things that you might find desirable, like small shrimp, feather dusters. In this article it states that they are generally reef safe if kept well fed. Reef butterflyfish