(You still pay its costs.)
Since [Zendikar Rising]s a land set, one option is always a land, but it lets the other side be an effect that might be too narrow to play by itself. That meant the Magic team could create more cards that both fit Zendikars theme, but also created chances for niche abilities
The cost reduction is reminiscent of Ghalta, Primal Hunger, and the ability to be on the beatdown while also dealing with planeswalkers is straight out of Questing Beasts playbook
Need to remove an attacker - or multiple ones
Hearthhull, the Worldseed turns land-sac into powerful card draw
The Star Wars universe has already been successfully translated into a variety of tabletop games, including a card game, proving that it's good for more than just digital media