For those of you who are familiar with the Meyers-Briggs test, I am an INTJ, though a number of the criteria are close to balanced. For those of you not familiar with it, that means I tend to be introverted, intuit things and see the big picture, value objectivity, and plan things well in advance. One of the habits of INTJs is that we tend to have only a few close friends, who are often INTJs themselves. So it came as no surprise to me that, when I took a job that required making collection calls (phone communication being typically anathema to INTJ folk), the response was overwhelmingly along the lines of "Holy crap, WHY would you do that???"
For what it's worth, I even asked the same question of myself, because I hate talking on the phone. It's impossible to use or gauge reactions to nonverbal communication, such as body language, facial expressions, gestures, and the like. Instead you have to rely on tonal inflections, which are very easy to fake. There is also the problem of communication lag, or feedback, or bad connections, which make conversations awkward and halting, situations that INTJs typically avoid like the plague. Last but not least, you're talking to people you don't know (awkward), about fairly personal issues (money and medical history), and there's a good chance that, once they figure out who you are and why you're calling, they're going to hate your guts and be rude just to get rid of you. Why would someone choose to do that?
For what it's worth, I even asked the same question of myself, because I hate talking on the phone. It's impossible to use or gauge reactions to nonverbal communication, such as body language, facial expressions, gestures, and the like. Instead you have to rely on tonal inflections, which are very easy to fake. There is also the problem of communication lag, or feedback, or bad connections, which make conversations awkward and halting, situations that INTJs typically avoid like the plague. Last but not least, you're talking to people you don't know (awkward), about fairly personal issues (money and medical history), and there's a good chance that, once they figure out who you are and why you're calling, they're going to hate your guts and be rude just to get rid of you. Why would someone choose to do that?