In the field of coaching there is more and more research that shows that when an athlete is in an environment where they feel supported and where they are having fun, skill acquisition comes more easily (for an interesting talk on this, listen to this podcast from Olympic coaching educator Wayne Goldsmith).
This is not to say that practices are or should be all fun and games. There is still plenty of hard work and workouts that at the end of the day are difficult and not necessarily “fun.” What the research shows, however, is that if the athlete is engaged in the process, the tough stuff is easier to manage, and the skills are easier to acquire.