No, the techniques- both physical and psychological- definitely work. Confidence can enable you to not care about your stutter and live on with your life; but if you desire to also eliminate all stuttering behaviour, then from what I've seen and experienced, some kind of technique(s) works best. What I will say, is sometimes the techniques may not work, if the fear/block is strong enough, or they haven't been sufficiently drilled. But you can certainly get it to work.