The average mana value of a shrine as of The Last Airbender is about 3.3, so you generally get 7 mana worth of permanents into play for 4 mana
Board wipes may not be as desirable for aggressive decks that go very wide, while single target removal may be less useful if the opposition fields decks that don't have any single high-value targets but instead have a lot of small threats and engine pieces
Giving Nights Whisper the meme of Sleeping Squidward is perfect, with his incredibly bloodshot eyes taking up almost the entirety of the card
The price you checked three months ago might be completely irrelevant today
Creatures that produce tokens get slightly better in this deck due to The Ur-Dragon, Dragonlord's Servant, Dragonspeaker Shaman, and Herald's Horn offering mana discounts, but I've found that the best token-producing cards are ones that can flood the board and attack immediately, which is why cards like Secure the Wastes (on the end step before your turn) and Tempt with Vengeance are my favorites
In those environments, it will serve as a sort of value-generating card that sometimes just steals games by doing an Overrun impression, which leaves a lot to like