Or lasers, standing in front of a radar installation, getting fried by a giant toaster. Take a tiny piece out of you and cook it in a microwave then put it back. Harmless? What if it came from your central nervous system?
Even though your proposition is outside of the scope of typical cell phone use, I would likely live just as long as I would have lived without it, given that its radiation is A) non-ionizing and B) not focused.
As an example, you could spend 14 hours a day in the sun to no ill effect, but only about two minutes with a magnifying glass focusing sun rays onto your forehead.