BTW, smartphone, phone, iPhone... The main function is a phone. Maybe calling is just the most important feature
So not true. These things we carry with us everyday are mobile devices...Not just phones. The phone feature is just one of the many functions of the device. But it doesn't necessarily have to be the "main function" nor the "most important feature" by any means. Maybe the most convenient feature, but not the most important.
I'd be willing to bet that most people use their iPhones for other non-phone functions more then they do the actual phone.