When a trained musician looks at a manuscript what they see is different from an untrained musician. We see patterns, students see notes. We see chords, chord progressions, phrases, texture, context, similarities and differences with repeated ideas, form and structure. Students see notes. I could go on. In short training brings understanding, understanding brings insight, insight brings joy to the musician and the listener.
You've got to learn your instrument. Then, you practice, practice, practice. And then, when you finally get up there on the bandstand, forget all that and just wail.
I'm a professional pianist and music educator in West Toronto Ontario. I'm also a devoted percussionist and drum teacher.