I don't share your confidence of that assessment, but it would warm my heart to think so.
> people should be allowed to consider whether there is any internal logic to the opposing position without actually committing to it.
I'm gonna stand by this one, I think, and disagree with you, although I think I see where you're coming from.
What I see a lot more than testing for internal logic of a position is people advancing their sole, or only substantial discussion point, with the "devil's advocate, but" position. If a consistency test is what you're after, you can attempt to perform an explication of someone else's position without advocating that position yourself, and without accidentally advocating it by presenting it unchallenged.
If I can omit the "devil's advocate" disclaimer and it still reads as a position earnestly advanced by the writer, then they are not playing at anything, they are making a real argument.