I dunno, to me, those "plain, vanilla duels" can, and will, take up a lot of space in the ic if posting back and forth, and may go on at least 2+ pages. Plus, it really gets in the way of others who are not in the duel and are just trying to rp normally. On the other hand, while a collab post does make a huge wall of text, I believe it is a lot MORE efficient to do so than to post back and forth. It doesn't drag on for pages, you can do it in private and come and go at any time, and we can read it all at once without other people's posts getting in the way. As a longtime Yugioh rp'er, I speak from experience.