The add on benefit, Halo 3 does not come with any kit. Do you mean Halo 3+ which does include Complete WiFi and Hybrid Connect.
With complete wifi there is no compulsion to use the black complete wifi discs.
With Hybrid Connect then if it is not left on then it will not automatically fail over to the 4G modem. It cannot fail over retrospectively, so turning it on after a failure will not work.
The recommendation is that you should leave it switched on all the time as you could miss software updates by turning it off and unless you have a full fibre (fttp) connection you could upset DLM resulting in a slower connection.
Having said that, with energy prices as they are I can see many people turning their kit off overnight, myself included.