Easy Assembly and Stable Stacking: Shipped flat for safety, these UPC protectors pop into shape within seconds
You cant play in official tournaments without sleeves, but there are official sleeves with the same art as card backs
One nonArt Card and nonLand card of any rarity is foil
You get a temporary creature, sort of like Fading, if you are old enough to remember that mechanic, except these tick up with lore counters and get additional effects
Of course, forcing players to sacrifice their creatures, adding your own sacrifice outlets, and mana generation will help Sephiroth overpower your opponents
If you want to dig further into calculating EV for a specific box, you can utilize resources like MTGStocks or check out the youtube video below, which does a great job of explaining a few other details you may want to consider when calculating expected value