Some of them grant powerful effects when you roll high numbers, while others care about how often you roll
Fast Mana Fast mana is one of the most common ways to end a game of cEDH, even if it isnt directly the thing that wins
Cartel Aristocrat is the better card in these kinds of deck but Yehenni is easier to cast while fitting in more versions of the deck and that is pretty much that
If you are able to bargain, bounce, or Break the Spell before the final chapter, it simply exiles a creature and provides the Chapter II bonus as well
There aren't a lot of good answers to four-Willpower characters though, so in a lot of cases Don Karnage can run away with a game all on his own
Many control decks could be crippled or even outright beaten if you caught them with their win condition and catching their only mass removal spell could be devastating as well