As a musician, one thing you learn to do is to play beyond your ability, to stretch yourself beyond what you would normally play, because it stretches you mentally and physically and helps make what you do play that much easier and stronger. I rarely if every play scales as fast as I physically can, at least not when playing live in a group. But years of practicing scales at high speeds has made me able to play them at slowers speed much more comfortably. Music is full of such exercises, things you do that make no sense from a musical sense that stretch you, mentally and physically, to go 'beyond yourself' that have the effect of make you much more confident and assured and graceful and musical at the playing you actually play to make music.
A perfect example is Miles Davis "Kind Of Blue", it's not a technical endeavor by any means; John Coltrane is one of the featured soloists and I've heard him do stuff much more physically demanding, but he could make his playing on "Kind Of Blue" so powerful because of the chops he has, even if the music is not a raw demonstration of those chops. A musician of lesser chops would not be able to play what he played, even if it was technically with that person's grasp.
In music, there are often three kinds of musicians:
Those who show disdain for chops, for technique, as being unimportant. Those are often the ones who don't want to put the time into practicing stuff that's hard to do, or just can't do it, so instead they put it, and people who do it, down as a way of protecting their own ego.
Those who practice long and hard at their chops and theyfall in love with their own raw technical ability to the point that it's all they really notice and it's the yardstick by which themeasure themselves and everyone else. They are often yound and musically immature and don't have the experience to now how to harness their talent into something that people actualy will enjoy listening to
Those who spend hours and years of hard practice to perfect ther chops, their technique, but who then use their talent as just a tool to make music that people enjoy.
So yeah, I set my metronome to 40bpm and practice just hitting whole notes, half notes, and triplets. It sounds really stupid but...it perfects my timing and my ability to play with positive and negative sound space and open space. I'll sit in my room and play scales a lot faster than I'll every need to, or even do totally atonal finger exercises at high speed, totally ugly sounding stuff that no one will ever want to hear. They strengthen my fingers, they loosen my hands, they increase my familiarity with my instrument, and occasionaly I stumble on something that actually sounds fun and could be musically useful.
I guess if I were to evver hear a musician saying "well I don't do scale exercises fast because I'll never need to play that fast" or "I don't practice with a metronome because we don't use a metronome on stage anyway" I'd be thinking to myself "well, you ain't goin' far, kid".
You always go beyond were you need to be so you can bring it back to where you need to be with confidence and precision and strength.
At least....that's the way music training works, and I've so far a lot of simularities between music training and martial arts training
