Although the paper’s abstract makes that claim, I really didn’t find it that much simpler. I think the “simpler” claim comes from the fact that the color and luminance adaptations to the illuminant take place in the same space, unlike CIECAM02 where there is an additional conversion step to Hunt-Pointer-Estevez space before applying the post-adaptation non-linear compression.
That said, at least the formulas are clearly described and the whole this is not all that many steps. I was able to reuse a lot of the CIECAM02 formulas “as-is” (e.g. determining hue quadrature).