Each time you proliferate, youll be further reducing the size of your enemy creatures that have -1/-1 counters on them
On one hand, this deck is well-suited to dominate games that go long
For a card to become a sideboard staple, it either needs to be the single most efficient version of an effect (Natures Claim), have a particularly backbreaking impact on the targeted deck (Stony Silence), or be so broad as to have an impact in multiple matchups (Rakdos Charm)
A shop buyer can sell the top chase easily, but the box becomes easier to merchandise when there are several cards that look good in a display case, binder page, or break menu
Blue Sun's Zenith works similarly, either milling an opponent out completely or letting you refill your hand at an insane rate