> This drove my high school typing teacher nuts [...]

I think that's typical for over-achievers.

I think it's how it should be done. You just executed the task intuitively, without any preconceived instruction as to the "best" way to do things.

Most of the time, those selling the best way to do stuff have a rigid way of thinking/operating and seem to have rules for everything in life and they think it applies to everyone the same, even though we are clearly all different.

Very often it's actually counterproductive and doesn't get you much better performance, touch typing is one of those things. It's a rigid theory made to form human robots that would spend all day typing stuff from other peoples (basically secretaries, re-copying stuff or typing dictated material). It focuses on typing speed at the expense of everything else. And is completely pointless because the speed difference between a touch typist and a self taught typist is completely negligible for 99% of tasks.

Pianists are very (like 60%) susceptible to RSI, especially if they have small hands [1] (= lots of stretching motions). I think it's a tradeoff — moving your forearm around spares your wrists, but puts more strain on your elbows. I wouldn't be surprised if it's better overall, though, just because it involves a wider variety of movements.

[1]: https://pubmed.ncbi.nlm.nih.gov/12611474/

Anecdotally, I have large hands (or at least long fingers) and early piano lessons, and as a self-taught chaos typist on QWERTY I struggled with RSI at a relatively young age until I switched to more traditional touch-typing on Dvorak.

I have small hands. I found myself sitting next to a chaplain once, and he started conversation with "your hands are small. You'd never be able to play piano." I was playing Beethoven in recitals at 8, TYVM! I ended that chat pretty quickly.

You may just be lucky :)