Phoenix is a crazy strong addition to the X-Men swarm strategy already enabled by Utopia, Uncanny X-Men, and "To Me, My X-Men!". She meets a strong efficiency baseline with her stats and easily adds about a resource worth of value with her enters play ability assuming there is another X-Men ally to target with at least 2 THW or ATK. There is no tempo penalty either as the ability comes with a ready to use that ally right away. Given the abundance of great allies in the game, I would only play her if I had an X-Men team deck, but in that deck she is one of the best allies you could possibly play.