If a case proceeds to Court, you can get due process, excellent legal advice, well developed case law - and a long wait and hefty bills. Mediation is a process to help parties to agree a way out of a problem. It takes parties outside the adversarial system, facilitating a deal away from the costs and process imposed by the litigation system. Parties can walk away having won something, albeit by conceding something else. It sounds ideal.
Mediation works when it creates an environment in which parties can settle their case.
But mediation is not right in every case. People negotiate best when they have good information with which to make decisions. Strengths and weaknesses in a case can be evaluated and informed trade-offs made. A deal is always possible but trying mediation while uninformed increases the risk of mistakes. That risk might inhibit a productive negotiation.