The benefit of the breath weapon on Blaze Dragon is that it gets stronger as you hold your primary attack button. It will start by dealing the normal 10 dmg continuously. After a few seconds, Sunburn will automatically engage stage two damage (Intense Heat). And this is the beginning of the failure of this path... at every upgrade stage your character starts to slow down. By the time you hit stage 3 damage (Phoenix Grand Blaze), you can barely move. The upside is that you will deal RIDICULOUS damage at this point - 30 damage continuously and infinitely thanks to the Infinite Flame upgrade. Sunburn will also start to self-immolate, meaning that anyone who touches him will take 30 dmg as well. If you get hit, you fall back to stage 1 of your breath weapon. Since this attack is the only real way for Blaze Dragon to deal damage, it's a serious problem.