Why use a ring light?
A primary advantage to ring light use is the shadowless lighting we mentioned earlier. Though shadowless, it isn’t flat. The lens (or phone or your eyes) sit in the middle of the light source. This means that the light source surrounds the optical line of sight.
Thus, the light is falling on the subject from every direction. Eliminating the shadows means you can clearly see the details that may have been obscured otherwise.
Even in a non-photographic situation, like applying make up to someone, this non-directional light source is a useful tool. Position the light near the model, look through the inside opening, and apply the make up with full knowledge of how it really looks.