Although known for being a thorn in an opponent's side, Rhystic Study's abilities are much more manageable and balanced in Wilds of Eldraine's draft environment with the heavy focus on enchantment interaction
You can either use it to counter a non-creature spell, or kill the creature you couldn't counter
With a high devotion to blue and ways to self-mill, this card is a superb alternate win-con
If 3 is chosen, then it can only be damaged, enchanted/equipped, blocked, or targeted by cards that have a mana value of 3
I think its got a lot of potential in the 99 of various lifegain decks (both Trelasarra, Moon Dancer and Elas il-Kor, Sadistic Pilgrim spring to mind), but I could also see this as the commander of a creature-centric mono-white lifegain deck too