With Esper Energy, as with any spicy new MTG brew that finds its way to success in Modern, the question of longevity is always close at hand
Historically, Mill has only been viable in draft when you are able to further your game plan of dumping your opponents library while simultaneously interacting with their threats
Then put a charge counter on this artifact
While the effect is simple on its face, it opens up a lot of possibilities in the right situations, stopping your opponents from using that characters powers requiring exertion or questing or challenging with them for another turn
There are other modal double-faced cards in the set as well
Including meld alongside typical transforming double-faced cards (DFCs) had some challenges, but I felt the need to fight for the version of Fang and Vanille that best captured their story and its impact on me