It needs to be built specifically around and is typically quite slow to yield returns despite being so cheap to cast itself
Well, it's because you can easily slot a few Mutavaults into your list - an MTG land that can become all creature types - to supercharge the card
I mean, you could sac your infinite Plant tokens to get the card you need to the top of the deck with Seer, but you'd need a Top to actually get it to your hand to cast it
gives you a green blue deck with tons of landfall and manifest cards, rewarding you for doing the most boring action in Magic, playing lands, by turning them into manifest dread triggers off of Zimone, Mystery Unraveler or turning a facedown card right side up if you play two lands in a turn
Targeting a creature with an ability was trivial, and with Springheart Nantuko backing Nadu up, you had a constant source of new creatures to target with abilities that cost zero mana to essentially draw your entire library
The catch is that this card needs a mana to activate its ability