joshi tm:
exactly the same what it does for backgammon game.
let's say you have 150 points and there is only one turn left for you and the only empty slot is
6's in the upper portion of the scoring table.
Your opponent is going to roll after you and he/she has 140 points so far and the only option is to go for 40 points (big straight).
What are the options for you ? You may get 18 points fairly easily or maybe 24 with a good roll, so you score may go up to 168 or 174 ...
Opponent, when lucky, can get 40 points and outscore you with 180 points ... without a doubling cube you go for win/lose result but with a doubling cube you may force your opponent to resign and get your win without risking a losing game. If an opponent accepts your doubling cube he/she take a hudge risk of losing 2 points since to get 40 points is problematic ...
there many similar situation during the game that may call for a use of a doubling cube ...
I hope it explains my thinking ...
What do you think now ?