> but as an amateur jazz/blues/rock pianist for the past twenty years or something, it's not going to make you a better player.
Knowing theory won't necessarily make you better at playing music in a certain style on a certain instrument. But it will make you a much more adaptable musician who can pick up styles and instruments faster, communicate musical ideas more efficiently, and form a mental conceptual model of a piece much more effectively.
Particularly in music as harmonically complex jazz, if you can't speak the language of theory other musicians frankly won't be able to communicate with you on paper and thus won't take you very seriously.
Now if you want to play for example punk or Appalachian folk music and nothing else, I would agree with you. But a working musician these days needs to be adaptable.
Knowing theory won't necessarily make you better at playing music in a certain style on a certain instrument. But it will make you a much more adaptable musician who can pick up styles and instruments faster, communicate musical ideas more efficiently, and form a mental conceptual model of a piece much more effectively.
Particularly in music as harmonically complex jazz, if you can't speak the language of theory other musicians frankly won't be able to communicate with you on paper and thus won't take you very seriously.
Now if you want to play for example punk or Appalachian folk music and nothing else, I would agree with you. But a working musician these days needs to be adaptable.