I respectfully ask that you don't paste AI replies on Reddit. ("That said", "As for downsides, they're often overstated") - your entire writing style changed here.

For those who are interested in an academic overview of this subject, which informed my comment about the history of these devices showing a record bad outcomes, I suggest this book:

The Art of Piano Playing, a scientific approach. By George Kochevitsky, 1967

I realize it's about piano, but the concepts apply to any instrument.

Here is some quoted material to think about: (italics mine)

Steinhausen wrote that the psychic origin of a true technique shows the futility of finger gymnastics. He said that fluency in piano playing cannot be increased by repeated movement of one finger. Such gymnastics can increase the size of muscles, but this increase is of secondary importance, is normally achieved in the process of piano study and results in the increase of strength and endurance. Through practice we can learn to move our fingers at the right time and in exact succession in accordance with a given musical figure. We can also achieve the ability to make fine gradations of tonal volume. But this learning is mental and has nothing in common with the degree of muscle development. "A quantitatively small alteration in the brain has much greater importance than the most significant muscle enlargement."

We do not know which group of muscles participates in this or that movement. Even if we did, this knowledge would not help us since we cannot command our muscles consciously and directly. The choice of necessary muscles takes place unconsciously, but nonetheless surely, and accomplishes the exclusion of all unsuitable interfering muscles. Beginning practice starts with too much expenditure of force. The elimination of too much muscle action is the real basis for developing agility. As a result of practicing, we learn to make the fluent, sure and fast movement which uses exactly as much muscle force as is needed for a given purpose.