There are many art forms that are similar to juggling. These skills are challenging to learn - requiring discipline, focus and practice. A skill focused on accomplishing an impressive feat. It will be hard to make a living and even more difficult to make a lifelong impact on people.
I argue that mastering any skill, no matter how inconsequential, will only benefit you. Working towards a tangible goal, seeing improvement and expecting perfection will serve to train your ability to grow and learn.
These ‘fun’ skills are fundamentally the same as logic, accounting and organization. The outcome of the training and practice is obviously different. The steps to go from amateur to skilled professional will be nearly identical.