Pop Quizzes in Academic Job Market Interviews

Many academic job interviews include a little section in which the interviewer tries to ask questions for which a job candidate is unprepared (this presumably is not the same as the section in which people are asked about their dissertations). I guess one reason for these types of questions is to see how bright the candidate is and quickly s/he can come up with good insights on the spur of the moment. Here's a recent example, posted by Alex Tabarrok about what he and Tyler Cowen asked:

At the AEAs Tyler and I would ask our job candidates what countries do you think are currently overvalued and what countries do you think are currently undervalued (in terms of growth prospects, reasons for investment optimism etc.) Many candidates were surprised by this question.

I've been on hiring committees. I've done the same thing, so I do not mean to single them out. But I am not convinced this is a good way to find out who would be a good hire. Most academics have little need to be quick on their feet/seat. If we screw up in the classroom, we go back to our offices, figure it out, and correct ourselves in the next class. And for research, we mostly take interesting puzzles and look into them in depth over some time. If we want to determine who can do this well, why not give them all a question (like the one Alex and Tyler used) roughly 48 hours before the meetings begin and let them prepare a bit?

But possibly another reason to ask questions like this is to see whether the candidate has thought about anything other than narrowly defined coursework and thesis work. If we want to hire people who have intellectual curiosity and breadth, then the interview pop-quizzes might be a reasonable filter.

Or maybe it's just fun to ask these questions so we can discuss them with the candidate, and doing so has nothing to do with the hiring process other than finding out who is fun to talk to.