Other: I often find these sorts of questions useful as a way of clarifying my own understanding of related subjects, and I think clarifying understanding can lead to pragmatic value even in the absence of an agreed-upon answer.

That is, sometimes it is useful to go from "I am confused about X" to "there are three possibilities (X1, X2, X3) and I know what each one entails but I don't know how to choose among them", even though the question remains equally unanswered.

This is similar to your "interesting debate" option, I suppose, but different enough that I felt uncomfortable picking it.