Plus its Ability can help you evolve Pokemon faster or attach energy cards more often
Since Jeskas Will only costs three mana, you will have additional resources to deploy the cards you exiled before they disappear
Mashing two games together like this can run the risk of feeling disjointed, but when I played Ravnica: Clue Edition myself I was impressed by how the deduction system has been used to incentivize a certain kind of behavior in the Magic game specifically, that behavior is to play lots of creatures and make them fight
In the event that you are pressed for life, even in a Commander game, Sylvan Library still lets you draw two cards and put two back, at the very least improving the quality of cards in your hand for a turn or two
While it can be useful for stopping specific cards, it is largely to niche to be that useful for a player compared to other spell cards
Notice how the black of the mana symbol is completely black throughout