She has a ton of built-flexibility as a result
Compare that to popular Elves like Yeva, Nature's Herald (4983), Timberwatch Elf (1689), Ezuri, Renegade Leader (2019), and Edric, Spymaster of Trest (4362)
Pact of the Serpent can either be used to draw you a ton of cards or kill an opponent, depending on the number of Squirrels you have
Its not hard to build a deck around it or to add this card to a Niv-Mizzet Reborn deck because they legends care about roughly the same suite of cards
It also comes with a kicker cost of three generic, one blue, causing your opponent to mill half their library rounded up
This deck can generate absolutely massive value by multiplying all of these different triggers