If you can find a way to deal damage to it, it can trigger and prevent a player from gaining any life for the rest of the game
The War Doctor can become a potent attacker depending on how many cards you manage to phase out from either side of the field
The prevalence extends to Commander, with a ton of cards released that help bolster up the archetype in that format
You do have the option of Cycling it as a regular counterspell, but at six mana thats arguably an even worse rate
Charred Foyer // Warped Space joins the ranks, offering no extra utility on the front end, but giving you a mini-Omniscience once you unlock the second half
Numai Outcast can grow to a 3/3 if blocking/blocked, but the regeneration cost on it is insanely high (five life!) Takenos Cavalry can at least function outside of combatbut only to deal one damage to a Spirit