There are differences between traditions of therapy and hypnosis. Hypnosis is almost always very brief and takes only a few sessions. It is for people who are more comfortable with their own emotions and grounded in reality.
Traditional therapy can be lengthy in that it allows a person to present their emotions, often for the first time, in the therapeutic session. The therapist often is working to allow the client to acknowledge the underlying emotional issues. After this, the client may be more able to adjust those emotions. After the emotions are on-the-table, many therapists feel their job is complete, and the client will be able to process those emotions. This theraputic dialog has gained main-stream support and is essential if you need or want to know what psychological issues you have.
Hypnosis is designed to even go below the emotional level. Down to the level of the values that make your emotions important to you. Remember, you did learn your emotions as a response to your own life history. Sometimes your history let you learn stuff that just cause you to have, well, inappropriate emotions. That is, inappropriate for your life as you want to live. Through Hypnosis you relearn and release issues relating to anger, guilt, fear, hurt or sadness that have been learned throughout your life. This has the result that you can move ahead in your life.