This card is used mostly in decks that like to copy spells for the Expansion side, and its nice to have that on rate with the potential upside of the other half
Also, low mana value changelings do exist
All this sacrificing means youll also probably want some Recursion, too, so consider adding cards like Black/Green cards that will help you get things back from your Graveyard such as Phyrexian Reclamation, Greenwarden of Murasa, Reclaim, Regrowth or Skeleton Shard
It also has protection from white, which is very relevant considering that white has a lot of good creatures and spot removal
Skithiryx, the Blight Dragon, and Tinybones, Trinket Thief, are both extraordinarily powerful cards
It also has a death trigger, its a lot cheaper on the mana, and it has the fun dredge