When you pair it with sacrifice outlets like Witch's Oven, you can suddenly start generating card advantage at will to out-grind opponents
It can only draw you a card on each end step, but in the right deck you can make it happen on your opponents' turns too
Incredible spot removal, and potential card advantage, all rolled into one versatile package
Starting out by being cast as a creature for one generic, one blue, one black, and one red to cast, Bolas can then be transformed into a planeswalker by paying four generic, one blue, one black, one red to transform
While we do have one additional mythic (Nicol Bolas, the Ravager gives us a total of 16 in the set rather than 15) and there are a bunch of random Planeswalker Deck cards that are technically part of Core Set 2019 (but not found in booster boxes, so they don't count toward our expected value calculation), there's one huge exception: the Buy-a-Box Promo Nexus of Fate