It's a lousy idea to base a deck on, because it's too slow. If you really need to kill that crimson dragon or something, it can be worth it, though, and if you're facing sundials, dimshields, SoSa, etc, you can eat the phoenix when it's not doing anything anyway. It's a good idea to keep in the back of your mind for unusual situations, but it would be ineffective as a main strategy.