The birdsong book makes sense, but I'd have to see what they added to William Styron's
Lie Down in Darkness that Styron would have wanted to include if he could've.
I was really keen on DVDs with extras when they first came out, but I quickly got over it and realized that 99 times out of 100, all I wanted was the movie. Since then, producers seem to skip extras on most movies, so apparently that concept proved to be more trouble than it was worth much of the time.
Really, I'm happy to just get the book and, if I want to know more about the author or whatever, to go the internet at home. I'm talking about fiction, here, and the stuff I usually would read in paperback. Travel books, picture books, textbooks, reference books...I can see multi-media being helpful with those.