It makes sense to promote multiplayer usage. It just kind of sucks really.
I wish there were a few more playground games though as it's pretty shallow. A championship is four rounds, but they only have three events. King, infected, and flag. They couldn't think up anything else? Lawn darts, demolition derby, cat and mouse, etc.
Then there's only three locations too. The terrain at these locations significantly reduces the types of cars you could realistically use as well if you want to be competitive.