Humans have colour vision because we decended from apes. Apes develop colour vision because of co-evolution with plants. Plants use colour to signal if their fruits are ripe, and apes use colour to find those fruits, eat them and spread the seeds.
Actually "Color" provides more information and hence better decisions for survival, growth and prosperity of the specis.
There are cells inside the eye which work for different perspectives, different optical perspectives. Cells for color, and cells for blac and white, because black and white are not actually colors. They are the to andbottom of a spectrum that are neutral.
