Emet-Selch, Unsundered may be a villain, but how bad can a villain be who constantly wants to make the use out of your garbage? He takes out the trash, but at least he’s going to make sure it goes to good use again.
It’s often hard to pilot a heavy surveil deck, because you of course want so many of the cards you’re throwing away. Hand fixing is great, and being selective of what goes into your hand can be extremely powerful. With Emet-Selch, he makes the decision easy. Your graveyard is your hand, so fill it up as quick as possible.