Bear in mind that if opponent got some non-shield removal (be that Oty who just happens not to care to get poisoned, Firestorm or whatever) Physalia will deliver some damage outright where Chrysoara won't. Or in lategame topdeck where you need to sneak in just a point or two, there is a difference.Plus, the Bone Shield is one of the most used ones throughout the PvP side of the game, and if you'd like your Arsenics to get through, physalia will take charges off it where Cry won't.