AbigailII: Your logic is unfaulty ! However, things can be seen for another point of view : cubed backgammon IS backgammon, and single games are the degenerated case of matches to one point.
I take "degenerated" for its mathematical meaning, it is not supposed to be insulting to one-pointer lovers :-)

But of course you are basically right, there isn't a bigger difference between Triple and Single than between Cubed and Single.