If I were building or buying a new home one important factor for a family with young kids is to have a place for the them to get outside to exercise while staying safe and clean. And theres many ways to provide an area like that, especially for the area where a swing-set would be placed or monkey bars. Either place you would want to have a safe surface to prevent injuries should there be a fall.
I have seen these kinds of mats on playgrounds areas that have a soft cushion like surface, like rubber tiles, bonded rubber and the like. Another type of surface is something that is used in industrial situations, that work in any conditions with bog mats for temporary roads and surfaces, constructed with High Density Polyethylene and insure a safe temporary work surfaces.
But there are similar mats and tiles that can be used at home for safe playground areas for protecting kids should they fall and are easily assembled locking together pieces like a puzzle and much better than grass. They come in different densities depending on your needs. They come in lots of colors that can be worked into your landscape. These mats and tiles can even be used inside your home in playrooms, there low cost and easy to install. Even a small area in a backyard will insure the safety of your children while they play.
They also prevent ground erosion and maintenance are easy to care for and last for years. For lots of ideas and uses I checked out Pinterest Play Ground Safety.