Does being a member of the ELCA sell books?

Andrew O’Hehir has an interesting piece in Salon.com about Bill Ellis’s book (Lucifer Ascending: The Occult in Folklore and Popular Culture), which points out, among other things, that the book is being sold with a back cover blurb that touts Ellis’ membership in the Evangelical Lutheran Church of America. So what I want to know is: does membership in the ELCA help to sell books? or establish credibility?