What is the current purpose of a bumper on a car?

Now that cars come in so many styles and sizes, the bumper is always in a different place. Some high, some low. Wasn't the original purpose to protect a car from damage during minor accidents. If the bumpers don't match up then it doesn't really work. Or am I missing something?|||For looks for extra smash material to soften a collision from doing real damage and for your air bags. oh also for lights and reflectors, and to keep nasty people from kicking your radiator.|||It's a cosmetic|||they are just for looks...the steel reinforcement behind them is what protects you...and the airbag sensors.