A busy kid needs to have their own downtime or relax time. Kids preference might be different depend on how they are configured *quote my husband’s term*. Some kids prefer to be physically active, go out, run here and there, screaming and just going around free will. Some kids prefer to sit in the corner reading their favorites books, while listening to music. Some kids prefer to watch TV or their favorite video, and some other might like to play computer game.
I guess, there is nothing wrong to pick which one they like. As long as they enjoy it and feel happy about it. The main purpose for downtime is to allow the kids mind to relax and rest. They need this from time to time, some kids need to have naps for this. Is all depend on which they prefer to do. As parents we need to understand which one they really like.
Have fun with your kids!