First of all, it's a green, 6-mana creature, so you can drop it early off mana rocks or mana-makers around turn four or five pretty reliably
Getting to choose when you incubate can mean the token isnt just removed, as is often the case for Phyrexian Rebirth
The kicker costs offset the life loss a little bit, but this sort of Dark Confidant style of card advantage tends not to work out well in Commander unless youre gaining tons of life or manipulating your library somehow
Cards like Sunscorch Regent, Yahenni, Undying Partisan, and Breena, the Demagogue all supply you with more counters while your commander Hagra Constrictor, and cards like them actually do things with them
This is one of the only true orc typal cards you'll find out there, though it has cross-synergy with goblins too
All of the Un- cards mentioned by me today are in current decks