From top-decking a single four-mana aura, you might suddenly conjure up a massive giga-threat with all your enchantments on it then when it dies, do all that again
Grasp of Darkness is a little better than Last Gasp, this can be worlds better than Doom Blade
This ability makes it a potential threat in certain matchups, and it can quickly grow in multiplayer formats where your opponents tend to run those colors
Cofagrigus can be obtained from Mega Rising: Mega Gyarados pack in the Mega Rising set
Both she and the alternate commander, Celes, Rune Knight focus on milling cards to the graveyard and then reanimating creatures to fill your battlefield
That can be a benefit, if youre looking for inspiration for your next deck, and a big jump start on the cards for it