1) I think it would be nice to have an option in the profile settings for automatic use of the doubling cube at the beginning of each tournament game.
2) This option would require another feature: if one of the players resigned in a tourney game within the first two or three moves then awarding of points should be irrelevant to whether the doubling cube was used or not.
1) The player who managed to click the doubling button first makes the opponent spend about a second on clicking "accept". Of course this second is not that important but it's quite annoying to have to waste it:).
2) Of course sometimes (very rarely for strong players) it's better just to resign immediately if the opponent has a much higher rating. In this case even after doubling a player should have several moves to resign with a minimum loss of points.