With 4.1 came this little incentive for Tanks and Healers(for the most part) to queue up for random dungeons to help lessen queue times for the vast number of DPS. The Satchel of Exotic Mysteries is a BoA bag received when you complete a Heroic while preforming the Call to Arms role. Contained within is Gold and low chances for Rare quality gems, Flasks, Elixirs, Pets and Mounts.
Let me share my experience with this. I'm normally a Ret Pali but today I decided to Tank and get these bags. I ran 2 Cataclysm Heroics pretty well and the group ran very smoothly. The same 4 players came along for my 2nd heroic as well so I'm fairly sure I was doing well. Lol. Anyways, once I finished I checked the contents of the bags. Both of them contained about 80 gold and a Rare gem. That might not seem too much, but considering that the normal gold reward for completing a dungeon is mostly spent on repairing after said dungeon this is an adequate bonus.
I only ran 2 heroics and came out with some extra gold. The bag has a lot of potential with selling pets it may drop, especially if you get lucky and obtain a pet from the opposite factions Argent Tournament pets. The bags are certainly worth it for Tanks and Healers when the role pops up, and the Call to Arms feature is a decent incentive for helping to lower queue times.