I like to participate in street races here in Chicago and many of them will set up a miniature race for the kids. I think it's a great idea because a lot of these are family events. Riders will come out with their partners and children and you want everyone to get in on the fun.
I also think it's great because it introduces kids to the sport of bike racing. If they can learn to love it at a young age they might grow up to be serious racers and advance the sport. Also, mostly, they are just cute to watch.