It's not surprising. The Dear Author folks have always been ebook proponents. They have a link for ebook posts prominently displayed and Sony is a blog sponsor. And since folks who read ARCs are, by definition, voracious readers, they do seem prime material for the ebook market.
So, if a publisher can provide the ARC as an ebook, why can't all books be ebooks as well as print? One of my favorite mystery authors, S.J. Rozan, has a new book out: The Shanghai Moon. Guess what? Hardback only! (Well, hardcover, and an audiobook, if I want to blow $30 on one book) Rozan has several recent books on Kindle, so I am hoping the Kindle version will be out soon.