The only thing which you absolutely have to have a hearing or deposition for, and cannot do by means of a Separation Agreement, is proving to the court that there are grounds for the divorce. The Separation Agreement can even state that the divorce will be on no-fault grounds. Separation Agreements are binding, forever, for both parties, except that decisions involving the children, such as custody and support , can always be changed by a court at either parent's request. Reconciling is another exception. If you resume living together as a couple, the Agreement becomes void, unless it includes a reconciliation provision that says it will remain in effect after reconciliation.
Reconciliation also destroys any grounds for divorce based on the earlier separation or desertion.
They are mostly used when people want to be legally separated but have religous objections to divorce. In addition, taking any legal information out of context, i.e., using it in a different court or a subtly different kind of case, or without the training to understand all of what it means or doing research to verify it, usually has disastrous consequences.