While I think the whole "you have to wait for him" mechanic is a little goofy since he's only a 6/6 vanilla, drawing cards makes your Act of Treasons potentially cycle (or better in the case of the ones that steal a bunch of dudes!), which is an absurdly cool effect
We can easily put multiple lands from our hand onto the battlefield and that alone is too powerful
If a foe doesn't have a hand, this does nothing to fill it, so that's pretty nice
However, despite the powerful ability, the cost to get him rolling is high even by Commander's standards
Paying one mana to bypass an entire casting cost is why reanimation remains one of the most feared strategies in the game
White has gotten more blink support in recent years, with Ephemerate finding its way into more and more decks as a value play