CelTan

flaneur said:
 One semi-technical area of debate not yet covered here, or left unstated: How does your phone differ from your filing cabinet, your closet, your car, your safe -- all of which are open for inspection by investigators with a warrant?

The government can have access to my filing cabinet. 
However, if I use a cipher for all my files and the only place where the cipher is kept is my head, then the government looks at funny sounding words on paper. 

The same as the government can take my phone but not force me to remember my passcode. 

There is no security without full, complete end2end encryption. 
And as other said, as soon as it becomes public that any government can have access to all your communication, those that require privacy, like corporations and crime organisations will go for their own proprietary encryption and just make an app for communication. 

The only feature that I don’t understand is Walkie-Talkie - having people's  watches randomly announce messages does not seem a good idea in any environment.
I set mine to absolute silent and rely on the haptic feedback to get my notifications. 

Also: messages already supports voice messages and I can listen to them at my convenience on any of my  devices.