This doesn't impact the board much on it's own, and even if it's giving you food, finding a turn where you can sink a bunch of mana into it and use it's ability is going to be a rarity
This is a case where a guy (in this particular scenario, Eli Kassis) got his hands on some uncut sheets, thought it would be rad to create some home-made bling, and cut them up professionally with intentional sheet misalignment
Terra makes you mill 2 each turn, but if she deals combat damage, you can pay 2 colorless to return a creature with a Mana Value of 3 or less into play tapped
Its close to unplayable outside a mono-black shell, and theres the occasional mana value restriction on what you can get, so it has its drawbacks
Maybe thats because pretending to fight giant scorpions and the Kraken was just the thing for my friends and me on those long summer evenings when it gets dark before your bedtime