At the library I want to see a list of all the titles in print from my favorite authors, I just use the local WiFi to get the data. For larger downloads I ask on the WiFi, but get the data over the visible light network. So I can see the text of all those books, DRM allowing. Or watch a lecture on the Great Bustard.
At airports, my PDA/phone gets all the flight updates on an endless loop, via the visible light network. At Home Depot I'm offered product information and How To videos. I'd love to see the view from the cockpit in real-time while I was flying. If we build really high capacity broadcast networks (like the over-the-air TV used to be), then we'll find uses for them we've never thought about at all. This may even make a computer useful in a class room.
I don't believe most of this requires encryption. Mostly an asymmetric network gets us video and large data requests over a cheap, local, and very limited range network. If you want encryption for small slices of data, us the WiFi to do a key exchange.