The disadvantage of making a Binding Financial Agreement is that you give up the right to have a Court decide for you, about the matters you have dealt with in your Agreement. This means that the court cannot take into account matters which it otherwise would because you have decided to control your own affairs.
For example, lets say you have stated in your agreement that “each party will retain all their right title and interest to their superannuation entitlements and have no further claim on the entitlements of the other.” You can’t then change your mind and ask the court to make a decision about giving you a piece of the other persons Superannuation, without first attempting to have the agreement set aside.