I use it ho properly disconnect from mobile network, if something not working with it on iPhone, disabling and enable mobile network did not do the trick, don’t know exactly why.

Because the cellular tower icon disables mobile data, but not the radios. You can tell because when you turn it off you’ll still see bars (if, you know, the radio is working).

Airplane mode on iOS disables cellular radios, but leaves WiFi and Bluetooth on. Your phone will sit there blazing (figuratively) as bright as the sun in its cellular radio spectrums trying to hit a tower when you’re 35,000 feet up, eating up your battery and potentially fucking with cell towers as you fly overhead, where WiFi and Bluetooth won’t. It also prevents potential interference from the 2G radio with the ILS the plane uses for landing (as I saw elsewhere from a pilot).

They have to pay ManU player salaries somehow..

Every once in a while during a flight, I'll get an email or a text gets through after a brief connection with a tower. That or my time zone will update based on the tower is connected to.

Now the charge you a premium for wifi.

I see at most a 1% difference with wifi on. It's better but doesn't "kill" from what I've seen. And not a lot of reason why it would.

Phones are a bit different (or at least used to be), as cranking up the transmitter power to try to reach towers, and other things that avoid sleep and cause extra usage really will make a big difference. Particularly higher power usage than normal when idle (i.e. screen off, etc). But for desktops/tablets/consoles, I don't think we see the same thing. ESPECIALLY if they're in active use.