What is so important about that fact? It is basic knowledge, that in a radio based system, like Wifi, Bluetooth, ZigBee, … you need to be near the source. That

What is so important about that fact? It is basic knowledge, that in a radio based system, like Wifi, Bluetooth, ZigBee, … you need to be near the source. That is called physics. With some techniques you may passively can monitor radio waves, but for active attacks you will always need to be close by. That is called physics in general and specifically electromagnetic waves.