Just for reference you should always wear your seatbelt if you have a car w/ airbags. And keep your feet on the floor where they belong. One of my biggest pet peeves is people who ride in cars with their feet on the dash... not allowed in any car i'm driving.
Also airbags explode with so much force because they have to deploy so quickly... you're really not supposed to hit them as they are expanding... but hit them once they have expanded... one of the reasons you need to wear a seatbelt.
and just so you know the explosives used in airbags are very powerful and very refined although typically slower burning that gunpowder and crap like that.
And as for why cars have them.. because the gov't made them. Auto companies probably never woulda used them if they weren't made to.
