Answer: It enables them to cover more of the visible light spectrum and therefore be able to harvest more light energy.
Pigments can be defined as the molecule that absorb specific wavelength of light or they are substances produced by living organisms that obtain color from selective color absorption. Thus, the function of pigment in plant is photosynthesis and they use green pigment chlorophyll with other pigments such as yellow and red pigment which are being used to captures much light energy as possible. However, plant gain from having much more than one pigment because it enables them to cover more of the visible light spectrum and therefore be able to harvest more light energy.