That only needs a local wireless (or whatever) connection between the reader and the light. X10 et al did this over power lines over 20 years ago. Communicating

That only needs a local wireless (or whatever) connection between the reader and the light. X10 et al did this over power lines over 20 years ago. Communicating over 802.11 - with or without the internet - adds complexity and exposes the device to the world.