When the point has been prodded to death by some argument, it lets your fellow arguer back-up and poke it from another side. Maybe my argument is wrong, but myself and the person I'm arguing with haven't figured out exactly why yet. This lets us keep circling looking for weak points.

Hopefully over the course of that we both come away with a deeper understanding of the idea itself.

I think of it like when E. coli run and tumble over the course of the hunt for food. Sometimes a random walk is a weirdly great way to discover the mechanism of how an idea works or doesn't work. I'm just occasionally flipping the switch on the 'tumble' circuit: https://www.mit.edu/~kardar/teaching/projects/chemotaxis(And...