Interestngly, the new PADI blurb on the new PADI OW materials emphasizes teaching of skills in new positions. Strangely enough, Standing(!) is one of the new ways they are emphasizing as a possibility. I'd quote the article but it is direct to the instructor communication from PADI, and I don't want the dark overlords to shoot me down.
I'm pretty sure you can quote that without a problem. There really isn't any more information about it in the quote than you wrote here. It has me mystified as well. I can't think of any skill I would prefer to teach standing.
Of course, there was the infamous Dive Training magazine photo for their story on underwater navigation, showing two divers standing on the ocean floor looking t compasses. Maybe it's related to navigation, since at least one trade magazine seems to think it is not possible to take compass heading while neutrally buoyant.