You say this as though I plan to just sit there and spam the "You can't hurt me" button all day long. I would have hoped that to one with an eye for detail as yourself would see that I am a highly experienced player, with a penchant for what makes fights and character interactions as awesome and cinematic as possible.

That said, the defenses only last for a single action. If you have a long-term thing such as a spell that conjures a lightning storm or a city-consuming vortex or whatever else... I would have to sit there and use perfect defense after perfect defense... spending motes faster than a crack addict spends their welfare check... all to simply avoid harm.. Damage-over-time and AoE are this character's Kryptonite. While she CAN hold out against it for a time, if she focuses purely on defense, she's fucked in the shitcan. Example being that Nuke I presented earlier. She could easily ignore the blast itself... but what about the resulting shockwave, residual heat, radiation, etc.