And let's face it -- when you're given a box of something, you really expect something to be in that box. Gold just doesn't cut it. Apparently Blizzard agreed with this sentiment, and the caches, deemed "failbags" by some, have been adjusted on the PTR to offer something far more substantial, according to a post by Bashiok on the official forums.
Trash drops, consumables, pets, and mounts? Count me in. This change ought to make getting that cache of items a heck of a lot more appealing to players. After all, if you get a surprise box of goodies, it ought to be full of fun!