There are a few different reasons kids have to want to participate in sports. One of the biggest motivators is to be a part of a social group while others are just looking for a hobby to do after school. Some kids are looking to see how their skills compare to other kids.
Kids are most likely to have fun when they are playing with other children while doing challenges. They are less likely to have fun when doing drills one on one with a coach or just with their dad in the boat.
When kids are getting started or while they are young, games should be heavily encouraged. Kids tend to want to become more involved if games are the focus. Playing games with their peers can encourage skill building as much as or more than drills can. In the earlier stages or while they are little kids, the games and challenges keep them interested. Hopefully that will inspire them to continue on for other reasons such as the love of the sport and competition.
Skill development really takes off when kids naturally want to improve their skills. Too much training just for skill development can take the fun out of what your trying to accomplish. Playing games and doing drills helps training from becoming boring for athletes.
If practicing is not fun, an athlete can become obsessed with routines and forget why they are training and practicing. However, if an athlete gets too comfortable and enjoys a familiar practice routine, they also may forget why they are practicing! When playing is not a part of the training an athlete may get stuck in the training mindset which is not ideal.
The purpose of playing games, skill building, coaching and instruction is to develop a confident and competent athlete who is prepared for competition or comfortable enough to reach the next progression of their ability.
Keep it fun, be sure to be creative and mix in challenges and games to break things up!