With that being said, many treatments that are used in therapy today do have empirical support from researchers. These treatments and their application to various diagnoses have been researched over many years. Keep in mind that the training curriculum of current and future therapists is usually highly influenced by the available research and trends for that treatment.
Both patient and therapist should care about evidence based therapy for the simple fact that we have access to treatment modalities today because of contributions by many practitioners, researchers and patients in the past. Both patient and practitioner have immediate influence over the outcome of their own therapy sessions. Evidence based therapy is the means to communicate and contribute to the effectiveness of therapy for others now and in the future.