Why learn to juggle?
It is a fun physical activity which is good for your body (coordination and balance) and your brain (mental agility and creativity).
It is a challenge. Learning to break down a task in its essential elements and then to build it back up correctly and have clear evidence of personal achievement is how all successful learning can be enjoyed. Showing others and passing on the skills is the foundations of true knowledge. Having the desire to expand your abilities and investigate more and more is where mastery is secured.