well 8bit is 256 colors, 16 bits is 65,536 colors, so it does matter, but you have to acknowledge that 8bit is using les bits as the equivilant in 16, which is logical when the 16 bits has more colors variable.
Also the difference between rgb and cmjn is also color varient, rgb is more oriented to screen when cmjn is for printing, (there is color in rgb that are not printable)
Hope this helps