I paint on my MacBook LCD, but I paint in 16bit and I dont use all white or all black because I know my image will go back to my CRT for final color correction.
Aren't we using digital cameras these days?!?
Yes we are in some films, but many still use film. But even if we were stricktly using digital cameras we still use 4:4:4 HD cameras like the Genesis that basically create 12bit color pallette that still is beyond the gamut of CRTs and further beyond LCDs.