What is the purpose of this conversation?

M: Hello. I need to talk with someone about my driver’s license.
W: Yes. How may I help you? Do you have a driver’s license, or do you need to get one?
M: Well, I’m not sure. You see, I have an international driver’s license.
W: Uh-huh. And how long will you be staying in the United States?
M: Probably four years, until I finish my degree.
W: Oh. Then you will need to get in Arizona driver’s license.
M: Do I have to take a driver’s test to do that?
W: Yes, you do. You need to come in and take a written exam and an eye exam, and then you need to take a road test with a parallel parking test. Did you say that you are a student?
M: Yes, I’m a student at the university. I don’t have an ID with me, but I can go and get it.
W: Okay. Then you can apply for a limited license. Just come back and show your student ID, and you can apply for a five-year license. The limited license only costs you ten dollars. A regular license would cost you a lot more than that, but it is valid for more than five years.
M: Why can’t I just use my international driver’s license?
W: You could if you were just visiting a lot less than a year. But as a student, you will be temporarily residing in our state.
M: Okay. So that’s why my friend can use his international license; he is a tourist.
W: Right.