I'm being sarcastic in the title. Lighting a roof arguably has little value in providing safety and security. In the case of Denny's in Temecula, their roof lighting is excessive.

The photograph below shows the Denny's in Temecula and their roof lights. Each light puts out a wide beam. Denny's uses 14 of these wide-angle, high intensity floodlights. On the far right, you can see the flare from one of these lights. Considering that the photograph is taken on an embankment above the building and off to the side by about 45 degrees, you can appreciate the wide field of these lights. Much of the light being used misses the roof and creates glare and light pollution instead.

A business has every right to use light for safety and security and to attract customers. Safety and security comes from pointing lights downward so motorists and pedestrians can come and go without interfering glare. Attracting customers can be achieved by lighting a sign; Denny’s has lit signs on their roof as well as a lit sign on a pole (not shown). These signs are more courteous and effective at welcoming customers than shining floodlights skyward. The latter mostly obscures the stars from us who enjoy the night sky or who conduct research at our nearby observatory.

The second best-lit roof award goes to Norm Reeves Honda. No matter how bright they make the light shown in this picture, it will still be dark under that canopy: