My understanding of this advice is something like: don't move the fingers up and down like little pistons with the rest of the hand are arm frozen and motionless, instead use the motion of the full arm from shoulder to finger tips, let your arm and hand drop into the keys using gravity to provide the energy.
That is easy to understand. It's easy to execute if the rhythm is slow.
When the tempo and rhythm of a passage speed up to something like scales in sixteenth notes at a quick tempo it is simply impossible to play each note with a gravity drop. If you could do that, your arms would be moving like some kind of shaking fit.
Whenever I hear this advice about 'don't play with the fingers' it isn't put into context regarding speed of the kinds of passages to play.
I found the video below which I think gives a very clear demonstration of gravity drops. I marked out a few key moments. (No criticism of the video, I think it's excellent and helpful.)
It's the very last segment that concerns me. Clearly she is playing by moving each individual finger. Her arm is not dropping with each note. The important thing seems to be that she is not lifting her fingers. She simply strikes the finger downward and then lets it return back to a neutral position. The effort is to strike the key, the finger returns to its starting position by a relaxation, a sort of release of the effort to strike.
If I am wrong, can someone give a detailed explanation of what I fail to understand?
Otherwise, why is the common advice 'don't play with the fingers' instead something obvious and direct like 'don't lift the fingers high' or 'move fingers just for the strike then relax back to a neutral hand' or something to that effect?
An exaggerated demonstration of playing from the fingers with lots of excess motion lifting the finger up from the keyboard...
Playing with the whole arm using gravity for the energy to strike the keys...
Medium tempo scales where there is enough time to lift the whole arm and gravity drop each note...
But, finally, when playing scales at a fast tempo there is no gravity drop, the fingers are used to strike down the keys, but only in a downward direction without wasted error lifting the fingers high