White balance is the only concept in the method that I feel I could understand better.
We want the palette to be in the same amount of light as the subject. That I understand.
This ensures a high level of realism when the final painting is completed. White on the palette matches white on the subject, matches white on the canvas. I know this concept borrows from photography.
Suppose you wanted to paint a subject under colored lights, for example a combination of blue and red on either side of a still life for a special effect, or a theater show under colored lights, or a rather dim gloomy still life.
How would you balance whites then without altering the subject? Wouldn't you want your palette well lit even though your still life is more dim?
What would the effect be of painting a subject that is under low or colored light? Perhaps something lit with 2700k bulb or lower for a warmer look?
Where would white balancing come in a scenario like that? You could put your white wood block in the subject, but it would be darker, or begin at a darker value than the white on the palette.
What would the effect on realism be?
Does white or the value have to equal the palette?