Since light bounces off walls and is thus confined to individual rooms, there is less interference and higher bandwidth, and traffic is harder to intercept from outside.

But, if light bounces in every obstacle, it will be confined to just a room or so… Then, I think is unreliable for the general public and will be only useful in specific situations… Which I can’t think of a single one… Not getting interference with Military, Hospitals and Airplanes isn’t already achieved by separating special frequencies for WiFi and Bluetooth? How that is achieved today?