Will Work For Color
Color Manglement and Working Spaces.
Let's not forget the many other color appearance models and methods. CAM02-UCS, RLAB, LLAB, IPT, CAM16 which is Luo's work in progress, etc. Many choices beyond the 44 year old Lab. The fact that Lab is one of the PCS used in ICC profiles is notwithstanding. If you look through profiles, you'll see that Lab is typically used as a PCS in profiles for CMYK and printing, while RGB space and monitor profiles use XYZ for the PCS.
Among other things, XYZ is computationally simpler than Lab. XYZ is infinite/unbounded••, you can transit through it without much penalty assuming the same source and destination illuminant (D65), here the fact the PCS is "D50" is essentially irrelevant: we are never really "in" D50, just passing through. Gamut mapping, soft clipping, etc. are usually not a huge concern going from a D65 RGB to another D65 RGB especiall