The value here is that it untaps on other players untap phases, giving you many more chances to activate abilities
The deck also features a number of evasive threats with powerful abilities such as Niv-Mizzet, Parun, Crackling Drake, and League Guildmage
Faeburrow Elder and Selvala, Explorer Returned are the most reliable of Selesnyas mana ramp options due to their low mana cost, but both also need to tap to generate mana, so youll need a way to give them haste to access their mana generation on the turn you play them
But Greninja is a dual-type Pokemon that can appear as either a Water or Dark energy Pokemon, depending on the set/game
Creatures get tapped when they attack, but not when they defend, and a tapped creature cannot be used to defend in turn