Lighting can make all the difference in the world to a photograph. It makes a photograph instead of a picture. The addition of the hair light in this image brings out the detail in the hair and adds depth, separating the subject from the background.
All the additions made to modern digital cameras do not add and place extra lights on your subject. This is why you hire a professional to create your images. The have the knowledge, experience and equipment to provide what you want and need.