That assumes that I put one set of lights on and just leave them. I have several front and rear lights and I change them out every few months as conditions change. Any system like this would lock you in to a manufacturer (a standard is possible but hands up anyone who thinks that Cateye and Lupine and Cygolite will all join hands, sing kum-ba-yah and build a common standard).

Wireless assumes built in battery for the light, which isn't true for me most of the time. I'm not willing to put up with the low battery life of the small batteries inside lights. Also wireless will draw power at all times as the receiver runs listening for the "turn on" signal - though with BLE it may be low enough to not make that much difference.