it's a renewable source of nova, that should, of course, cost more and be more vulnerable. Because, instead of card slots in your deck, it would take permanent slots on the field. Thus making your deck faster and easier to play. Not only that, it let's you play a mono deck but use any 2 mana or less card outside of the color. At most, you can pack 6 novas in your deck and you still have to draw them. With the compressor, you could achieve a similar effect with 1 card.