[AndrewC]

Early cells may have used membrane pigments to protect themselves from the then intensive UV. ... Okay, so UV light is not only not a problem for the formation of life,

If it is not a problem why have protection?

[gomaaa]

Read the next sentance. The same chemicals that would protect a cell by absorbing UV light could easily be used to provide energy for the cell. These chemicals are nothing particularly special. We have specialized pigments in our eyes for seeing, but similar chemicals give our skin color and power photosynthesis in plants.