The Color Pie is used to ensure new cards are thematically in the correct color and do not infringe on the territory of other colors
You also want to avoid committing Energy early on if you can afford it
(It's an artifact with ", , Discard a card, Sacrifice this token: Draw a card.") Legendary Creature - Vampire Rogue Moonstone Eulogist Flying Whenever a creature an opponent controls dies, you create a Blood token
Even without discounting or cheating it out to change the math, thats a solid exchange and if you have any way to recoup the life then youre off to the races
In practice, this card is expensive, does very little on its own, and is downright laughable in the Commander age
Blitzwings impact isnt groundbreaking, there are definitely better mono black Commanders out there that cost less than 6 Mana (Sheoldred, the Apocalypse being the latest hype Commander)