I can think of several issues
Presumably not all insurmountable, but off the top of my head:
Limited by line-of sight (or reflection)
No interference from EM radiation? What about the fact that light is EM radiation? Will receivers be 'blinded' by oversaturation from things like camera flashes, lightning strikes, or other rapid changes in ambient light levels? What about moths and other flying insects?
Eavesdropping - better have your blackout blinds and curtains shut if you don't want your neighbours across the street eavesdropping (okay, I know this is no worse than Wi-Fi, but still...)
Backhaul? How will this work? Will it need special light sockets with wired network, or will it use Wi-Fi for backhaul? If Wi-Fi, what is the point - you're already using the Wi-Fi bandwidth, so why not use Wi-Fi directly? If wired, then will I need to rip all the wiring out from my lighting circuit and replace it? You could use IP over powerline, but that is pretty useless when lighting is on a separate circuit to your power sockets (with a breaker that has a different current limit).
What is the expected lifespan of one of these special bulbs? I know LED bulbs last a lot longer than incandescent ones, but I'm willing to bet they'll still burn out - either the LEDs or the control circuitry.
Biting the hand that feeds IT
