Mask someone's identity with an optical flare. This effect is often done in westerns. Character A looks at character B, who has his back to the sun. Character A sees the outline of character B standing in the sun, the bright optical flare masks the identity of character B.
Create a UFO or a light creature with an optical flare. In video editing programs an optical flare is often heavily customized. It can even be animated around the screen. Optical flares make excellent UFOs, stars, comets, light dust or even tiny light fairies.
Add an optical flare to create additional artificial light. For example, a production may film a person giving a speech but may only have one or two bright lights on the person. When the camera pans to face the lights, additional ones may be necessary to convey how bright it feels for the character. Optical flares are used to mimic a stationary light source.