It does a little of everything: Fills the graveyard with discard and self-mill, then rewards you for removing cards from it
Whenever you cast a spell with the chosen word in its rules text, you draw a card and you lose 2 life
If you have graveyard recursion, youll often want to chump block with your Chaplain to get it into the graveyard so you can get it back if you dont have a way to sacrifice it
This typically means mana-acceleration effects that will help you produce eleven mana naturally for someone like Ulamog, the Infinite Gyre when you can't bring him to class for Show and Tell
With Goblin Warchief, Goblin Chieftain, Impact Tremors, and Goblin Bombardment on field
Both halves here, the lands-from-library effect and the trigger doubling, are historically very popular with players