Players can call the summons for aid in battle
You can use Yuna, Hope of Spira, to reanimate them for free with a finality counter, or Rydia, Summoner of Mist to reanimate them by paying their mana cost
in a Commander game, they might just save their removal for a more pressing threat from another opponent
Trance Archfiend is special in that you can use its effect to discard a Dark World card from your hand, activating its effect
"Unlimited also had multiple print runs
As for Holistic Wisdom, green has a lot of recursion and while being repeatable is nice, having to exile a card from your hand means it doesn't generate card advantage like Eternal Witness and friends