All that practicing lays down the foundation patterns for playing any music in any key.
The part I loved were the etudes that took me through every permutation of a fingering pattern in every key. They were delightful and challenging puzzles that fully engaged the mind and fingers.
Since the early ’80’s I have been envisioning a transparent sphere big enough for a person to step inside with colored lines of light that connect all the keys and harmonic progressions together. They light up as they occur in the music.
I was the only one of my “group” who truly loved music theory. Now, I am preparing materials that will allow anyone, absolutely anyone, from the very most basic beginner onward, to lay down that foundation to enjoy how music all fits together.