The Reaper also has a brake to force you to lose life too when you draw the card
Incidentally, exile effects like these are also excellent against Deathmist Raptor, which is another major player in Standard alongside Hangarback Walker
After playing with both decks and trying out these cards in some others, I can tell theres a few standouts here
The massive card flow that people want for free in Commander and multiplayer lead them to attack each other, but not you, especially since they don't have to spend a card to get the card draw, so for them, this is free card advantage over time for each foe that attacks each other, and you'll draw more than the card it took to cast him in one or two turns
On top of that, Zacama, Primal Calamity is also a powerful attacker and blocker