Guess what: If Terrakion is OHKOed with 2 energy on it, you lose the same amount of cards as if you lost a Donphan with 1 energy. The difference is if you had been using Terrakion you would have taken a prize to keep up in the exchange but not if you'd used Donphan. Also, Donphan increases dead draws since you can get a Donphan without a Phanphy.