In a Vannifar deck something like turn one mana dork into turn two Tyvar into turn three Vannifar is a deterministic win with Prime Speaker Vannifar tutoring up a deadly chain of creatures
If your curve is low enough, you should be able to reliably get back quite a few cards if youve been filling your graveyard throughout the game with self-mill or other means
Also, as head designer Mark Rosewater once noted, the Ravnica: City of Guilds set was the first to make in-game factions highly cohesive and distinct thanks to their official names, watermarks on cards, and many cycles
Haste gives you an extra attack with her, vigilance keeps her back so the first strike and protection can work to keep people from attacking, and trample will smash through any measly defense you might have otherwise mustered
Those frogs add up, letting Quina boost itself with +1/+1 counters whenever you sacrifice one
With its introduction in Adventures in the Forgotten Realms it became a black-bordered mechanic
