Whenever the equipped creature attacks, Sword of Feast and Famine untaps all the lands you control, giving you mana open to pay for the Aggravated Assault and get another combat, which untaps the lands again, and so on
Itll also disrupt any top deck manipulation from cards like Brainstorm, Senseis Divining Top, or Vampiric Tutor, just to name a few
Ostensibly, white is the worst color at drawing cards, but then Wizards goes ahead and gives it this miniature Rhystic Study, which will ensure you stay ahead on card draw or keep your opponents behind the curve
So again I would not use this card in a deck, but if you choose to use it in any old darkness type deck, you'll just want to use the move that can give you the most damage every turn (or in the case of Push Down, can save you from major damage the next turn from your opponent)
We've been seeing a lot more of these auras that make things into tiny 1/1s, but the ability to exile the creature is a new one