I am not entirely sure that this is the right stack exchange, but I couldn't find any other suitable one - please redirect me if necessary.
There exists mathematically defined colour spaces which help us represent colors with accuracy/efficiency in computers, and different color spaces will capture different ranges of the human visible colour gamut, and because our screens cannot represent colors as raw wavelengths we must use these spaces instead.(correct me if anything said there is wrong)
How do these relate to how our computer screens actually show colour? From what I understand, our screens only take in N-bit RGB signals for their LCDs, so why do we worry about having all these complex, computationally expensive colourimetric spaces, when we want to do colour processing or storage etc. For example, the sRGB space has a gamma encoding, to represent a different data range with the same amount of bits... but that gamma encoding (for a greater range of dark tones?) cannot actually be displayed on screen. And CIE xyY might be excellent for spectrum based rendering and accurately producing and grading colours - but I understand that we cannot actually see their results, only RGB approximations. Again correct me if any of the above is wrong! I say none of this with much authority, which is mainly why I have to ask this question :)
We are storing different, nuanced, "perception correct", data in this 8-bit channel format - but is that extra nuance is lost as soon as we send it off to our raw RGB 8-bit channel screens, and if so, doesn't that loss invalidate (to some extent) all our extra measures to produce ever more accurate and wider gamuts?
This question focusses on R8G8B8A8 displays, as I imagine HDR would have a different story.