What possible operational benefit would that provide?
Not sure about iphones but on my phone if I plug it in rather than use blue-tooth, I can still make calls with on my zulu headset. Saves battery power on both headset & phone. Banning these devices is absolute BS in my opinion. Having just flown a round trip of Australia, being able to make calls for AWIS & in the case of comms failure (which has happened to me) is absolutely priceless. Would never go flying without now. However, I generally don't play music through it unless i am paxing with another pilot.