I look forward to li-fi being able to replace the physical layer for smart-home tech. Wi-fi, zigbee, blutooth, z-wave, they are all subject to interference and attacks from people physically outside the home. Li-fi is a lot harder to attack - its not perfect you still are vulnerable to an attacker standing at a window, but even then they can only get to a single room.
Ideally all the smart-home stuff would use a link-layer on the power lines, but only insteon has anything like that and its not restricted to power-lines, its more of a fallback to the wireless mesh mode.
