The good thing about round robin is that even though it's a little more time consuming, it doesn't have the flaw that pokemon or waseda style matches have, which is the fact they often show which team had the single most effective player in a given set, not which team actually was more solid. Besides that, it involves more matches and more fun matchups for people to watch, and that's what we're pretty much going for in an exhibition match, aaight?
Pokemon/Waseda style are much better suited for tournament play though, without a doubt (both for saving time & fairness).