"I'm not a huge user of the car's A/C system but during winter time I have no choice. Is the fact that the blowing of hot/cold air from the vents towards the phone implies that the phone might be impaired or slowly deteriorate? I have no idea if an iPhone, or any smartphone for that matter can be sensitive to heat and cooling."
First line talks about having to use the AC in the winter, no choice.
And does the heater hurt the phone if it's clipped in front of the vent?