[ekonine]

Learning music theory is different from correctly playing an instrument. If your goal is to produce then your method is probably good for dipping your toes in the water if you have literally no music experience whatsoever. Most digital production doesn't require you to play complicated passages for a long period of time, so you'd succeed in realizing your goals on that front.

But if your goal is to perform; sure, you'll be able to play simple compositions, but anything complex will pose a challenge without a teacher (or even good material that makes you aware of what to look out for). I think that's what your critics are trying to point out.

The real problem here is you're equating learning music theory with 'learning the piano'.