John wrote: "Authorship only plays a role with the "in-depth-articles" feature, and otherwise has no effect on ranking in web-search at all."
Google has been hinting at working on a good guy algorithm that may use authorship and forms of author or content specific authority to promote web pages. There is a good chance that authorship in this form or future forms, may play a role in rankings. Another point is that authorship may improve your click through rate because of the extra image in the search results.
But for now, authorship, outside of the very edge case of in-depth-articles, has no role in rankings.