I loved getting a new boxed game and opening it up to find gags, posters, puzzles, comics, stickers, a manual... even the brochures were nice.  I bought some merchandise that way.

There was even the rare instance when the screenshots on the box weren't in the game.  (I'm sure everyone is thinking of Spiffy the Dog in Monkey Island right now.)

I like that GOG gives you a scanned copy of the manual, artwork, wallpapers, soundtracks, avatars, etc.

I'm not complaining though ("Back in my day...").  Not having to stand in line at the store or wait for the post office is amazing.  The option to get the box for extra is sometimes worth it.