Safety is relative... Yes the car body can withstand a collision better than another small car, but that’s irrelevant when you are dead because the deceleration was so abrupt your brain splattered onto the inside of your skull and your ribs were turned to splinters that shredded your lungs.
Trust me, odds of you surviving an impact at highway speeds in one of these is next to nil. Sure they shell of the car may not be a mangled mess, but you will be.
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.