Should Greedy Venom Fusion Dragon be destroyed, you can destroy as many monsters on the field as possible and bring back a Level 8 or higher Dark monster from the Graveyard
There's a big advantage to sneaking it onto the battlefield, despite the cost, because when it deals combat damage to an opponent, you can pull a creature from that player's graveyard, which then enters the battlefield under your control, tapped and attacking that player
Tribal deck strategies rely on synergies between cards of the chosen tribe, in this case, Elves
Its sometimes useful even to goldfish it (this is stolen advice from Am I The Bolas, and it means dealing yourself a hand and playing by yourself on your own table, just to see how things might shake out in a real game), maybe even more than once
Includes a 7-card booster pack with unique cards to enhance your deck