The fact that you can choose the timing of the transformation is excellent
While for some decks, the graveyard represents cards that have been used or destroyed, for graveyard-focused decks, this zone is capable of functioning as something comparable to a player's second hand
Mark Rosewater (April 15, 2013)
This is a highly powerful and aggressive deck that focuses on building up an army of strong, aggressive vampire creatures, taking advantage of graveyard mechanics, Lifelink, and can come over the top in a stalled game with powerful cards such as Vona, Butcher of Magan
(9/25/2020) The copy is created on the stack, so it's not "cast" or "activated." Creating the copy won't cause abilities that trigger when a player casts a spell or activates an ability to trigger
Decimate and Casualties of War can take out multiple targets