[theamk]

It tells me which follow up questions to ask. If during introduction the candidate talks a lot about past job A and very little about past job B, it probably means they find job A more interesting, and it will make a better topic for conversation.

(When interviewing people, you want to ask them about things they are good at, so you can properly judge their level. Asking them to select which topic to talk about accomplishes that.)

Additional, some people are just uncomfortable for the first few minutes of conversation with any new person. Asking a simple question with no wrong answer can help them feel more comfortable.