Call For Backup has so many ways to give a ton of +1/+1 counters to your creatures, which makes practically every card in the deck a giant threat
Being this large for this price at the time was an outstanding deal, even if nowadays it doesn't look like much, and the bonus life points were like adding insult to injury, causing players to wince looking at their hand that little bit more and do it again when you cast additional black spells
Why you cant sacrifice a creature at any time in MTG Sacrificing is a game action that only happens when something tells you to do it
These lands can sometimes tap for lots of mana, first black mana equal to the amount of Swamps for Cabal Coffers and the other Nykthos can tap for any one mana equal to your devotion to that color
Extreme temperatures and humidity can damage your cards over time
As a huge fan of Adeline, Resplendent Cathar in Commander, Im definitely not against white getting a finisher like this one for go-wide decks in casual Commander