Airbags are supposed to be about cushioning such crashes... and so are the supposedly government mandated crush areas on cars. Are smartcars getting a pass on these crush areas? Some highway on-ramps have explicit warnings against unworthy vehicles e.g. bicycles and mopeds.
Airbags help you from smashing into the steering column, but they don’t help with the simple fact that a human body can only decelerate so quickly before things go horribly wrong.
Even if airbags prevent blunt force trauma (and they won’t) they cannot stop the fact your brain will slam into your skull when you decelerate to quickly. Your brain floats in fluid, this fluid acts as a buffer to keep your brain from hitting your skull under normal life experiences, a hit or a fall, but the human body was not designed to go from 65 MPH to 0 MPH in a few inches. That rapid deceleration may stop your body, but your brain keeps moving in that fluid and slams into your skull... Crumple zones and other things that other cars offer add just enough in most cases, distant to decelerate at a rate that will keep this from happening. In cars like this, where you literally are decelerating the human body so quickly, your brains buffer will not prevent it from splattering on your skull.
That airbag may be softer than the steering column, but in the situations with cars like this, at highway speeds your odds of survival are slim. Engineering cannot override physics.
Reality in any small car you are at risk at highway speeds, but the smaller the car is, the shorter the deceleration window is and the shorter the deceleration window is the more likely you aren’t surviving. Its nothing against Smart Engineers, they have designed the thing about as well as they could, but as I said, engineering cannot override physics.