I tried to dredge up some old topics to answer this for me, but found the opposite of consensus.
This post says yes, the Body of Argument roll in Duel of Wits is a graduated test and counts as a routine test for advancing the skill you roll.
This post says no, the Body of Argument roll can only count towards spent artha.
The “yes” post is from the Revised section of the forums, not Gold, but I’m not aware of any difference between the two that would impact this. So which is it?
My take would be that the rules do indeed still say “each player tests his skill”, implying that it should count for advancement as it’s a test and tests generally do. But maybe there’s a good reason why I’m wrong? They don’t explicitly say “graduated” or anything.