What you would get if negotiations fail often determines what you do get if negotiations succeed.
A party who can make a take-it-or-leave-it offer can get the entire surplus from a transaction.
Bringing other parties to your negotiations can radically alter the bargaining environment.
Giving up control can enhance your negotiating position.
Taking negotiations to the brink of failure can make credible a threat to do something that is not in your self-interest.