It gives all your creatures lifelink all the time which is extremely nice when it comes to recouping life paid for black spells or early hits taken while setting up your graveyard
Rev, Tithe Extractor, Gonti, Night Minister and Shirei, Shizos Caretaker all love this one, but I especially like it in Gix, Yawgmoth Praetor
I would say Ulamog is the second most competitively played behind Emrakul, with the Ceaseless Hunger defining the Standard format he was legal in for a while
Curve this into a pair of 1/1 pests and you have done a good amount of stalling and gained a pile of life
All sweet commanders, though
For this article I will primarily focus on Pioneer and competitive Pioneer decks going into the Regional Championships but I will also include some mentions for Modern or Jankier things to do in Pioneer