Why do people who build churches or any other religious building use stained glass

Stained glass are colored glasses in which its history of usage dates back during renaissance period. They are called 'illuminated wall decorations' as they trapped the light instead of permeating it to reflect. People build churches or buildings with stained glasses for (1) the art of glass itself as it delicately put colors on the figure it wants to portray and (2) because it controls light making the window more artistic. Using stained glass windows became more efficient and that’s why people opt to use it.