Without light , there would be noting in the world , there would be no food , there would be no life , there would be no colour except black .
What is the importance of light?
It is a prime factor in photosynthesis, which is what a plant uses to create the energy it needs. Without plants there would not be food for animals. The whole food chain would collapse.
It can also effect a person psychology. Not enough light can cause a form of depression call SAD, or Seasonal Affective Disorder, also known as the Winter Blues.
When I was young I had a pretty blonde girlfriend who was so light that I could, and did, carry her for miles.
She's no longer that light and I'm no longer that strong, so if she wants to go miles these days, she can walk like everybody else!
So light has the potential to make money for entrepreneurs like Jenny Craig and Weight Watchers. They just promote "light" with "beautiful" and people pay them money to be light again.
BTW the antonym for Weight Watchers is McDonalds.