Beyond the synergy and card advantage, the deck plays a handful of powerful cards in the 99, such as Black Market Connections
This one also happens to cover when artifacts go to your yard and there is a treasure subtheme to the set
This doesn't mean you should buy the decks to profitthat's unlikely to work, since Wizards upped the supply of Commander decks after the True-Name Nemesis debaclebut it does mean that a lot of expensive, powerful, and fun casual cards are going to get cheaperway, way cheaper
Choco, Seeker of Paradise I imagine Choco, Seeker of Paradise will eke out Kastral, the Windcrested as EDHs best bird commander, if only because adding green to the mix makes any casual EDH deck better
Devotion relies only on the color symbols in the casting cost of cards (in the upper right-hand corner)
It's also the only playable black spell that destroys enchantments