I can see this. Self-published authors buying the works of other self published authors and the sort of trade off that might happen. Nothing wrong with that. Personally, I can't see myself looking for self published books unless I hear about them somewhere else or know the author. But a whole database of only self-published books? I can't see very many people turning to that. But I know very little about self publishing. I think a website that reviewed self-published titles and kept an eye on market trends might be more useful and attract more users.