The benefits of musical training (for both children and adults!) are endless. PBS and the National Association for Music Education specifically lists the following as consequences of music education:

• Language Development
• Increased IQ
• Larger growth of neural activity (the brain works harder)
• Spatial intelligence (also necessary for math skills)
• Improved test scores
• Improved memorization scores
• Emotional intelligence and development of empathy
• Development of creative thinking
• Preparation for the creative economy of the 21st century
• Learning teamwork as part of a band or orchestra
• Being disciplined and learning a skill one can be proud of

Learn more by reading the full articles here:

http://www.nafme.org/20-important-benefits-of-music-in-our-schools/
http://www.pbs.org/parents/education/music-arts/the-benefits-of-music-education/