I'm not sure I agree that this game is more important to the Warriors than it is to the Mavericks. I think it's equally important to both teams.
For the Ws, if they win tonight then they maintain hold on "home court advantage", and they also keep up their confidence in their ability to beat the Mavs. If they lose, but lose close, they still have their confidence that they can play with the Mavs, and they have a chance Sunday to beat the Mavs and even the series at home. Yes, they would not have "home court advantage", but they already know that they can play with (and beat) the Mavs in Dallas.
For the Mavs, if they lose tonight they get behind 2-1, and their confidence would continue to nosedive. They would have continued to show that they cannot beat the Ws in Oakland, and they make sure that this is going to be at least a 6 game series. Remember, for the Mavs, they do not see themselves as successful unless they win it all. Going 6 or 7 games in the first round really hurts a team's chances of winning it all. So the Mavs are not just playing ot win this series, they are playing to win the Championship. They need to try to close this series out as quickly as possible, and not continue to let the Ws think that they are in it.
So it's at least as important to the Mavs to win tonight as it is to the Ws.