The colossal denizens of the deep in Magic: The Gathering occupy a strange design niche
Card Shows (The Cash-in-Hand Edge): Card shows are unparalleled for sourcing because you can inspect conditions physically before spending a dime
For Hearthhull, I think it comes down to the fact that this deck is dumping tons of lands into the graveyard and it most likely wins the game by bringing them all back in one go - using a card like Splendid Reclamation - for a mass of triggers
While it is usually more efficient to make the opponent draw a new hand with cards like Iono and Unfair Stamp to disrupt them, other cards care about the specific types of cards in the opponent's hand, and Whimsicott ex is one of these unique options
I would buff it somehow, and then it will clean out my opponent's creatures before it starts drawing me cards
Such high rate of interest in these lands indicates huge market speculations, meaning they may dominate the market in the short term