[WS:] It can be useful when you change your residences often. No need for changing your number and paying setup fees. Also when you are traveling, as pay phone have been eliminated for the most part. I use my smart phone mostly for email, which is my main mode of communication.
But I am in agreement with you about the need for mobile phone. Most people do not really need it, they use because they are addicted to it. Research on habit formation suggests that habit can be formed by patterns of gratification, even if very subtle. We tend to live a very alienated life - we are separated from others by cars, work cubicles, and suburbia. Even in public places people tend to avoid casual conversations with strangers because chances are that such conversation will quickly lead to a pitch for money. Ditto for land line calls. Since under US laws marketers cannot call mobile numbers, this is perhaps the only form of communication in this country that is reasonably free from marketers. Therefore, if you receive a call or an SMS to your mobile, the chances are it is from someone you know. This leads to habit formation like in Pavlov's dogs - each time your mobile rings or vibrates you associate this with mild gratification of being contacted by someone you know. This is why people call or text each other every few minutes even though they have nothing of substance to communicate.
A typical conversation on the Metro: "Hi, I am on a train. Will see you soon" carries no message per se, as the other party probably knows darn well how and when his/her significant other is coming back from work. Ditto for the conversations between teens - "Hi what are you doing?" "Nothing, I am bored" "Me too." In such situations, the only message is the ring itself that provides the recipient with instant gratification associated with the fact that someone wants to contact that person.
Paradoxically, the more venue of communications are being created, the more difficult it is for for people to actually communicate http://www.expressnightout.com/printedition/PDF/EXPRESS_06042012.pdf -- Wojtek
"An anarchist is a neoliberal without money."