Why do we have lawns?

The obscurity of having a lawn in modern time still boggles my mind. Why the hell do we have lawns? Maintenance cost and all these just sky rocketed during summer season. That is not to say it also takes in more water from the local municipal. On top of that, having a lawn also invites pest like ants, worms, spiders, and other insects. In addition to a bad economy it just doesn't make any logical sense. I'm seriously thinking of buying this product from this site: http://www.waterlessgr.com. Whoever invented the lawn is a F**king moron!