I don't profess to be an expert on safety but how many lives might this save?
I know the argument is that however few it saves it will be worth it, but how is this going to be significantly better than properly used seatbelts? Most accidents involve total hull destruction and I can't see airbags being very effective. I am sure that someone will cite the Afriquiyah accident, amongst others, and say there might have been more survivors than just the one young boy, with airbags, but it's highly speculative.
From my perspective I cannot say I would feel safer on a 'plane with airbags than with seat belts, it's down to the folk in the pointed end to keep me safe.
Perhaps if I had airbags like this to look at I would not bwe over-concerned about the safety aspect.