Whether you are a singer or musician, composer or sound engineer, you can benefit from understanding how to read and write sheet music.
Music theory is important if you would like to clearly share music with others or reproduce any given song with integrity.
Benefits For Singers
When we listen to a song on the radio, we are essentially relying on our ears to tell us how long to hold a note, which sequence of notes are being sung in a run, whether the artist is singing louder or softer etc.
All of is very interpretive and can lead to inaccurate replication of the original song. When you are able to read sheet music, all of the above are clearly marked and there is no grey area. It requires a lot of skill to sing the notes as written, but this makes you a singer with control and finesse. This level of musicianship is what is required in the music industry and professionals are expected to deliver these skills if they wish to be hired by any reputable producers, musical directors or professional choirs.
Extra skills like sight singing, (singing sheet music using a Do-Re-Mi system called solfège), form part of a valuable skill set for singers.
Benefits For Musicians
Pianists and guitarists can play by ear and follow lead sheets (with chord symbols) but when you understand sheet music, you are opening yourself to the universal language of music. Sheet music uses the same fundamental system for every instrument and also for the human voice. Learning music theory opens up a doorway to the entirely new world of music. You can compose new music, arrange a popular song so that it has your personal flair, you can appreciate the classics by playing them as the composer intended, or you can look at any piece of music and experience it for yourself.
A knowledge of music theory makes everything clearer and helps you understand and appreciate your instrument on a deeper level.