my fiance listens to audiobooks because they're an auditory learner. they really can't process words on paper, so the audiobook does more for them than a paperback would. if we got into technical terms, i think i do have a problem if they're saying "i read a book" but just listened to it as background. If someone is listening and grasping it well, they're reading it, in my eyes.
reading to me is more than interpreting words on a paper, it's actually getting something from it. and whatever method you use to achieve that, i approve of :)