Kids spend as much time at school as adults do at work. After they are sent home they have homework that they have to complete. While this regimen teaches them more, they need time for free play.
The time they spend unsupervised, in the real world teaches them how to act and use resources. They need the time and space to develop their personal awareness and skills.
Improves Language Skills
Outside, there are no boundaries in concept or how loud they can be. The only boundaries are the ones that the kids create, share and explore with one another. Even by themselves, they are free to imagine whatever they like and will attempt to share their creations. Interacting outside and with their peers, children are given a chance to explore and develop their unique voices.