I could go on for ever about the physical, emotional and intellectual benefits of playing music. Here are a few links about it. Check them out!
Music Benefits Last a Lifetime
The Top 10 Benefits of Playing an Instrument | Musicouch
Even without those benefits, I believe that not everything in life should be about performance, money, grades and social status. We should be allowed to do things simply because they bring us joy and make us happy. Playing music won't undermine children's performance in school. On the contrary. So why denying them that pleasure? It won't hurt your kid's grades to play 30 minutes of horn, guitar or violin per day even during exam periods. It would relief some stress and allow him/her to think of something else than maths for a little while.
We are put sometimes at a very young age in a race for money, success and social status by our anxious parents and teachers. Enormous pressure is put on kids' shoulders to perform in school and "become somebody" This is nonsense! There is a lot more to life than maths and science. At the end of the day, as the great Scottish educator and founder of Summerhill school A.S. Neill said:" someone with the potential and motivation to become a doctor will become a doctor and someone with the potential and motivation to become a street sweeper will become a street sweeper. I would rather Summerhill produces a happy street sweeper than a neurotic prime minister." Reading Neill's book changed my life and the way I approach teaching. Here's the link to Summerhill's school for more about Neill's philosophy:
A. S. Neill's Summerhill School
Children should have an indisputable right to fun! Sure there is a time for studying, learning and yes, doing maths! But there is also a time for playing outside with friends, playing music, watching TV or simply doing nothing if that's what you feel like doing.
I believe that happiness should be the real purpose of life. Money doesn't make people happy, music does!