My interpretation of GP's comment: Owning an iPhone doesn't make you stupid, owning it for just messaging and calling does.
I disagree, though. I have a number of friends with iPhones they use for little more than that, but they were free from their spouse or a family member. They either don't pay for a data plan or the data plan is part of a shared family plan so cost-wise it's a wash compared to dumbphones. They also happen to have a decent amount of storage (though not competitive with things like the iPod Classic until this latest generation of iPhone) so they can carry just the phone and have their music, calling and messaging in one device.
I disagree, though. I have a number of friends with iPhones they use for little more than that, but they were free from their spouse or a family member. They either don't pay for a data plan or the data plan is part of a shared family plan so cost-wise it's a wash compared to dumbphones. They also happen to have a decent amount of storage (though not competitive with things like the iPod Classic until this latest generation of iPhone) so they can carry just the phone and have their music, calling and messaging in one device.