Or you use wifi like a normal person. We call them phones because that's what they evolved from but smartphones are fully functional computers that we can use

Or you use wifi like a normal person. We call them phones because that's what they evolved from but smartphones are fully functional computers that we can use anywhere with ease, and using cellular data to make phone calls is only one small facet of their usage. For the overwhelming majority of people, being able to just pull up a map on their phone is the more convenient and preferred option. "Just handing you a paper map" is not so simple when you don't have paper maps because getting custom paper maps printed is expensive.