In a first glance, it does not sound as a good idea. Why would someone want to use visible light for data transmission and not IR? Bluetooth? FM?
Well, here are some nice ideas for visible light data transmission. You're in an airport terminal and you see the sign "Bluetooth" or "WiFi" with bright LEDs to indicate these signs. So you go with your compatible receiver and you get your flight details etc. - OR - There is the same kiosk illuminated with LEDs, and the same LEDs used for lighting purposes are also used to transmit data... Better right?
The receiver has a very sensitive light sensor. This prototype can be plugged into a smartphone or tablet, but it can be easily embedded in the future. Two-way transceivers are also available for bi-directional communication.
RF do not work well in narrow corridors and harsh factory environments with EMI from machines being constantly emitted. A light-communication system ensures that it will always work, as long as the light is visible.