Its a very juiced-up Millikin, and decks interested in self-milling will play this card for the mill and for the eventual god creature
Runaway Steam-Kin is great on turn-two and works great with Experimental Frenzy, but its very weak to removal and can be a bad draw later in the game
In this instance youre just resetting in terms of time and mana spent
Because Mirrormere Guardian and Enraged Huorn both tempt and have 4 power, Ents Fury plays well in green decks that prioritize those cards, and I think the best green decks prioritize all of those, as well as Generous Ent, Wose Pathfinder, and Many Partings
In the hands of a savvy player, the deck can be quite successful against other starters
The deck relies on support cards that help draw cards and gain life for your Book, such as Revitalize, Search for Glory, and Potion of Healing