Is it really that great for the doomsday scenario? If a person is in the same room and Bluetooth works, I don't need any special app for sharing files. If it is

Is it really that great for the doomsday scenario? If a person is in the same room and Bluetooth works, I don't need any special app for sharing files. If it is remote, I don't see how spawning a wide area mesh network should be even possible with the most recent generation of smartphones. The sending power is just too small.