The point of having the Preware Homebrew Documentation app in the app catalog is four-fold:
1) It is a good reference for new users, and saves me spending valuable spare time answering new user questions.
2) By being a 5 star rated app, it is noticed by people who have never heard of homebrew before and gets them interested and involved.
3) Since it is in the official app catalog, it makes people feel less scared about homebrew in general.
4) It benefits me personally in a financial sense (to the tune of around $100 a month - not much but it helps incentivise). See http://bit.ly/webos-phd for more details about that.