There has been much research that proves music lessons and musical training from an early age improves spatial awareness.
Research has shown that the motor cortex, the cerebellum and the corpus callosum (which connects the two sides of the brain) is more developed in musicians than in those who have never had the opportunity to play a musical instrument.
Music lessons improve hand/eye coordination and pattern recognition. All those scales and arpeggios really do come in useful!
There are also therapeutic effects of great music and from the various components of really great music. Variations in mood, pitch, rhythm, speed, tone, etc. can be both profoundly relaxing and positively uplifting and exciting.
The appreciation of great music can activate the brain’s reward centres and depress activity in the amygdala, reducing the effect of negative emotions such as depression and fear.
Furthermore children who grow up with an appreciation of good music as part of their experience really do end up smarter than those brought up on a diet of endless pop junk.