This has the potential to be a decent control finisher in a deck that can make other Powerstones to fuel Karns second and third abilities
You can tap Berta to create a beautiful, inspired representation of life in the pure form of a perfect Fractal, only for it to immediately collapse from a critical lack of ass
So if youre using The Ur-Dragon or Miirym, Steely Resolve will be a nice addition to your deck
Each of these cards has their own use in some way shape or form, and if you know your local pod relies on turning creatures sideways to load up on umpteen combat or attack-related triggers at which point they reach critical mass, surprise them next time
The risk here, of course, is that you're still two lands away from being able to cast it
The more complex the interface becomes, the weaker the card maker becomes in my opinionunless it offers some wild power to go with it