You cast him for cheap using delve, then keep using his activated ability to "convince" opponents to give you back what they think is safe
Dropping a [[Portal to Phyrexia]] early can end games, and this card lets you do that without convoluted setup
She turns the Madness mechanic into a high-speed card-draw engine
WB lifegain decks appreciate the extra triggers, and its also a town for synergies, so ramp decks can stabilize early and get the payoffs later
Starmie is the evolution of Staryu and it has an attack powerful enough to bring us one step closer to putting the practice duel out of its misery (I mean, of course, winning the very informative practice duel)
If I were to use this card in battle I would use Magcargo ex once, by using Lava Flow and discarding all three energy cards attached to it and do 100 damage and then slowly build up to do Lava Flow again