"Vanity's Emptiness" states that neither player can special summon monsters while it is on the field , effectively locking down the extra deck and making players completely change how they are playing that particular game
If youre playing a five-colour deck, this card is basically an essential addition
Deck Description We would like to thank AkamiVR for sharing their deck with the public
These characters were over, along with the campaign
That said, between ramps ubiquity in Commander, the fact that ramping one land for 2 mana has been good enough for many cards to see consistent play in the format for years, and the risk that Deep Gnome Terramancer will be a dead card is minimal at best, and Id call it a safe bet youll come out ahead far more often than not when playing this card
So how much more Arkham Horror CG do you need