It is very important for kids to have play in their lives. Because this way they are social with other kids, they also understand that taking turns is important. They will also learn how to solve problems on a day by day. They will also learn all the different types of emotions the have and how they are able to control them.
I li,e that you tied in the point about other kids. Parents are very concerned about their own kid and yet kids also need to learn to get along and learn BY playing with others, they pick up on things and learn so much through each other.