The Crawford Rule makes a big difference in some situations. Suppose that Black leads you 14-12 in a match up to 15 and that this is the Crawford game, i.e. Black reached 14 points on the previous game so you cannot double him this game. You have much the better of the game and have a chance of winning a double game. Normally you are prepared to take some risks in order to try and win a gammon, especially when you are behind. But in this case that would be quite wrong. If you win this game, you are going to be able to double Black immediately in the next game. Therefore it makes very little difference whether the score after this game is 14-13 in Black's favour or 14-all. The only difference is that if it is 14-13 he does have a free drop. But that is a small advantage and you are certainly not justified in taking any significant risk of losing the game, and with it the match, to prevent him getting it. The same principle applies whenever the Crawford game is being played and you need an odd number of points to win the match. If Black were leading you 14-4, for instance, in a match to 15, the only advantage of winning a double game would be to deprive him of his free drop. Once you get to 5 points, you only need five single games, or three single and one double, or one single and two double, and that is also what you need if you reach 6 points.
But remember that all this only applies when you need an odd number of points to win the match. If you need an even number, then a gammon is a great advantage and you should try hard for it.
The other side of the coin is also important. When you are leading, and the Crawford game is being played, then if Black needs an odd number of points for the match you need not be afraid of losing a gammon. So you can take any risk to give yourself the best chance of winning, as long äs you are careful not to lose a triple game.