Except we don't perceive the dimensions of color as comprehensively as we perceive multi-dimensional space. We can intuitively construct straight lines, planes,

Except we don't perceive the dimensions of color as comprehensively as we perceive multi-dimensional space. We can intuitively construct straight lines, planes, spheres, cubes and various other geometric primitives. We can't construct those things in color space without a lot of specialized knowledge. We basically perceive colors as similar or not, as well as a few basic attributes like brightness and saturation. If we're missing a dimension, we just can't differentiate between as many colors as other people. This is why people can go their entire lives without realizing they are colorblind. So, if you can compress the normal range of colors into the range that can be seen by someone with partial colorblindness, it could potentially make all the difference. Note also that magenta exists as a color (ie unique subjective experience), even though no monochromatic light can evoke it I don't think any light can evoke it, right? You would have to artificially stimulate the optic nerve to see it.