Is anyone buying an iPhone because it's slightly thinner than other phones? I've never heard anyone say the width of the phone was their reason for picking an iPhone, or any phone for that matter.
There are certainly people buying iPhones essentially for fashion/status-symbol reasons: i.e., because they look visually different from other phones, whether that is because of thinness or anything else. Why else would so many Android devices have copied the FaceID notch so soon after it was released?
Its unlikely anyone is buying a phone because of how thin it is (within reason), but it is quite likely that they are more likely to learn about a new phone available to buy if it is "impossibly" thin. Advertising is important — even for recognized names like Apple.
>Is anyone buying an iPhone because it's slightly thinner than other phones?
Yes. I have at least two co-workers that have stated (we will see if they follow through) that they are going to move from their current phones (13 Pro and 15 Pro) to the Air because of the thinness.
People who buy iPhones don't need a reason to buy iPhones other than just for the sake of buying iPhones. That's the key to Apple's trillions. Apple would have made this phone 2.75cm thick and there would have longer lines and same people singing paeans of thick phones and how it is going to change the world and solve global warming and eventually bring everlasting peace.
I'm strapping phone to my arms during runs; for me, shaving off those extra grams count. Bought an Infinix specifically for this reason. I didn't specifically look for the thinnest but it came the the most lightweight.