I'm thinking that the longer matches make the rating award more fair because it allows the luck a chance to even out and let the higher rated player supposedly better playing skills to make the points closer to the odds of their winning a series of games.

I've never played with this double cube, but when I did Backgammon we always counted gammons and backgammons though we didn't bet on the game. We'd usually just play first one to five game points. I'll have to get me a Backgammon set one of these days and see if I can get a game going. We usually play cards, so I doubt if it comes to pass. Least ways I still have BrainKing to play it on.