The goal is, in conjunction with Lands that can tap for multiple mana at a time, to Cascade into Creative Technique and ideally win the game on the same turn
The composition of a play booster looks like this: - 1 rare or mythic rare
The Ruinous Powers The Ruinous Powers deck is full of demons, board-wipes, and gets lots of value out of the extremely strong Cascade ability
The effect is always beneficial to the caster, but the opponent needs to pick whichever one benefits his game state better
Those extra cards can also help keep Nezahal, Primal Tide on your board for longer
Yes, there is an increase in price for the MH3 product compared to many other Commander precons, but this is a case where the purchase price leads to great value