Working in CMYK lets you avoid the stage where everything looks muted when printed because you didn’t properly account for the different gamut, and because nobo

Working in CMYK lets you avoid the stage where everything looks muted when printed because you didn’t properly account for the different gamut, and because nobody knows how to properly set up conversions. And beyond that, Adobe’s stuff knows about things like using spot inks outside of the RGB/CMYK spaces. Spot gloss, metallics, etc. Open source alternatives do not.