It provides mana fixing, card draw, and the ability to create land creatures if you need them
The main impetus for this was the failure of the Planeswalker Decks, with R & D concluding that a trading card games introductory product should probably have randomized booster packs rather than preconstructed decks
Hitting those magic KO numbers just became a little easier, and we could possibly see a 1-1 line (plus the Spirit Link) in other decks just to take advantage of this
Yes, cycling counts as discarding a card
Reality Shift is the one I think is most essential of the lot
It has gorgeous artwork, impactful new strategies and mechanics to try, and a host of rare cards any Pokemon card collector would want to get their hands on