I've heard the phrase "the real question is~" in various situations, but I do not fully understand why people say this. Does the expression have the same function as a punch line?

Native speaker’s answer
Rebecca
"The real question is" is used as a segue to move from one topic to another. It's used as a way to smoothly transition to a different topic while still on another topic. It does not usually have the same function as a punch line does. A: Do you see the shirt he's wearing? B: Yes, but the real question is how on earth does he fit into those pants! Ex: The real question is how do we get her to the party without her knowing.