Low growing jewel orchid?

I think the confusion stems from the color of the plant.....when you have a purple or red plant the cells still contain chloroplasts and chlorophyll. A plant may contain secondary pigments that absorb certain wavelengths of light better than green chloroplasts, but these secondary pigments are not photosynthetic. The secondary pigments facilitate photosynthesis but on their own they are unable to convert light, CO2, and water into the appropriate sugars for the organism to grow. This is not to say that because a plant is red it cannot perform photosynthesis, The red pigment is simply "drowning" out the green pigment of the chloroplast. The question of faster growth rate in relation to high intensity light and the correlation of more "color" is simply the fact that in a high light situation some plants may need less chloroplasts which equals less chlorophyll to perform the necessary photosynthetic process because more light energy is being absorbed per chloroplast. In turn they exhibit more color variation to shield themselves from the sun while still performing the necessary functions. So in an equal light setting a purely red plant vs. a purely green plant will grow at a slower rate because the plant is performing less photosynthetic reactions which in turn is equal to energy into the organism in the form of sugars. This is under the assumption that there is no other limiting factor like water or CO2 in either plant. Many other factors are involved. Through the evolution of different genera you may see adaptations that facilitate the growth of the plant including CO2 gas exchange and water retention properties. Look at succulents for instance, they are built the way they are so that when they receive water in their arid environments they can use it the best of their ability. Coloration is not the only limiting factor in the photosynthetic pathway but a very important one, just like the succulent will suffer in its growth from less than needed water, a similar plant may suffer even greater because of the lack of light energy received by having mostly secondary pigments and primary pigment like chlorophyll a. So more "color" does not equal more growth, chlorophyll a is still performing photosynthesis but at a much higher capacity.