One of Magic: The Gatherings most popular mechanics ever is kicker
Legendary Creature - Human Rogue Eriette, the Beguiler Lifelink Whenever an Aura you control becomes attached to a nonland permanent an opponent controls with mana value less than or equal to that Aura's mana value, gain control of that permanent for as long as that Aura is attached to it
Foil cards are inherently rarer than non-foil cards, etched or otherwise, which bumps their value up
Making Auras cost three less is quite the discount, and helps enable Enchantress decks to storm off by cantripping off of their Auras when they have Enchantress creatures in play
Heres a breakdown of the cards included: Grasping Tentacles A blue-black Sorcery card that forces a target opponent to mill eight cards
Theres all kinds of ways to do this, like using fast mana, an intricate combo, or a reanimation spell