Nature endowed food colors and the process of photosynthesis that helps create specific colors for specific produce does add to the taste experience (yellow tomato vs red).
Artificial food coloring is added to enhance the color of food for visual and appetite augmentation. Scientific research has proven that visual enticement and appetite are interconnected. Gourmet chefs place equal importance on, not only the preparation of the food, but attractive plating to entice the palate.
There has been considerable discussion and debate regarding artificial color enhancement of foods, since it involves additives unnecessary to anything other than altering the appearance of the food. At best, artificial food coloring does not change the fundamental benefits of food, but depending on the chemicals used, theoretically, any additive could cause harm if ingested by someone allergic to any component and the long-term consequences are not yet fully known.