So in summary, you would think you’re save when you disconnect your Internet cable from your PC when you don’t use the Internet, correct?
You are safe. The phone would not be able to use the hardware the killswitch is attached to, in this case the wifi and radio module.
the malicious software can send any data it collected while there was no network
And yet there are phones out there, that do have killswitches. Why? Because they have killswitches for the microphone and camera as well. Additionally, on the Librem 5 the GPS as well as other sensors are turned off. So even if the phone was infected and able to collect data, the sensors are physically turned off and useless.
I don’t understand this hate and scepticism towards hardware killswitches. Yes, you’re adding additional buttons to wear and tear, but in terms of privacy, they are clearly superior to software switches.
IMHO a killswitch is a gimmick to try to obtain more privacy and security, but fails by design.
I really cannot understand how you come to this conclusion, it is literally the only way, to work by design, short of not having any hardware able to communicate.
A smartphone inherently is a personal device with a network connection.
Yes, especially if you want to be available all the time. But there is no reason for example for the camera, microphone and gps sensors to be active all the time for a phone to still fulfil that purpose.
Just because you can’t be 100% certain you’re phone isn’t spying on you, doesn’t mean you shouldn’t try to minimize the data points it’s collecting. Privacy is not a black and white thing, many things inbetween exist.
The problem lies in software and who controls that software.
Even if the software is fully open source, you build it yourself, and it has been audited by a team of competent engineers, vulnerabilities or undefined behaviour can still occur. This is exactly what hardware switches prevent, so I can fully understand why some people would want them in their phone.