When there are multiple light sources in your shot, letting the camera automatically change white balance between, say, flourescents and incandescent lighting can be distracting. Locking white balance will keep your shot consistent, regardless of the color temperature encountered as you pan and tilt.
VideoPro Camera includes many more special features and settings:
Compatible with iPhone 4S, iPhone 5, iPhone 5c, iPhone 5s, iPad Wi-Fi (3rd generation), iPad Wi-Fi + Cellular (3rd generation), iPad Wi-Fi (4th generation), iPad Wi-Fi + Cellular (4th generation), iPad mini Wi-Fi, iPad mini Wi-Fi + Cellular, iPad Air, iPad Air Wi-Fi + Cellular, iPad mini with Retina display, iPad mini with Retina display Wi-Fi + Cellular, and iPod touch. This app is optimized for iPhone 5.