We wanted players to feel fear in gameplay, so we created dark transformations with TDFCs, and used mechanics like morbid to make players question actions they normally wouldn't
Likewise, Phage the Untouchable has an ability that makes any player who is dealt damage by this card lose the game outright
The intent was presumably that a 1UUU Planeswalker with no built-in protection or other loyalty ability wouldnt be quite good enough in the era of Teferi, Hero of Dominaria, but it was a viable win condition in Standard Kethis Combo, arguably the best deck in Standard prior to the 2019 rotation
This years printing of Aminatou, the Fateshifter took the core cards cards like Future Sight and Oracles Vault and added white and black, so I can do fun things like survive Duskmantle Seer longer than everybody else, get whatever I want out of Druidic Satchel, and break the symmetry of Zurs Weirding (since I dont need to draw cards)