Really, you should just buy a CB/VHF radio. As someone commented above, iPhones are not rugged enough for the kinds of use you might need such a radio in. And batteries can be changed/etc. They really are not expensive.
Yes but the idea/hope would be to minimize form factor as well as having the microphone and speaker being cordless. And for emergencies (unlike others I'm not looking to be social but to have another channel of emergency communication).
That being said I do own a marine vhf radio.