It looks like the script referenced by Pilou only creates the color styles, as stated in French it doesn't write to the geometry.

Eight !! years ago, Michael provided help in how to write color styles to objects, in one of the scripts that I was
working on. It was the Gradient script. Also used in the JacobianFunctionGraph script.

https://moi3d.com/forum/index.php?webtag=MOI&msg=5592.5

- Brian