I’m not sure that this provides any benefit from an EMSEC perspective, as you’d basically be going from a position where you’re avoiding radios and even cables and similar things that aren’t TEMPEST shielded for fear of emissions leaking sensitive data, to a position where you’re broadcasting your sensitive data over the air, and a listening device simply needs to look at your lights somehow. I will agree that it’s easier to block light than radio, but I think that’s where the advantages end.
I think you have this backwards. You'd still encrypt your transmissions same as if you were using WiFi, so its a wash in terms of security. But it should be much harder to jam your receiver/transmitter, because its point-to-point.
