If you crash at 25mph without a seatbelt I'm pretty sure that cage and airbag are pretty useless when your body is flying through the front window. But then again, you're not hurting anyone else, except anyone who cares about you and maybe the driver of the car which crashed into you who has to live with the fact that their actions hurt or killed you, rather than just crushing the front of your car.
I have to agree, though, those cup holders seem pretty useless;)