I agree with the person who posted previously.
Hypnosis is a technique whereby a hypnotherapist induces a trance-like state in which the practitioner becomes more susceptible to suggestion and highly focused on what they are being told. Though, it can be mistaken with hypnotherapy ocassionally. Hypnosis is defined as induced state of altered consciousness. Hypnotherapy is simply using this altered state as a therapeutic treatment. You can think of hypnosis as a claw hammer and hypnotherapy as pulling out a nail. It is a tool that can be used for many jobs whether its for entertainment, conversation or therapy.
So there are many uses for self hypnosis, including more basic forms. Personally I'd use self hypnosis toremove or Change Behaviours. Self hypnosis is a proven tool for eliminating behaviours that people deem negative or inappropriate. If you have any behaviours that you want to stop then using this trance-inducing technique is the key.
Removing Negative Beliefs is a less general form of self hypnosis which I still include in behaviour changing. Through self hypnosis you can easily influence your mind to eliminate these beliefs quickly and permanently. You can implant new beliefs into your subconscious mind easily using this approach.
Another common use that I know of is pain / stress relief. Hypnosis is used frequently within the medical establishment as a form of pain relief. As hypnosis and self hypnosis are essentially the same thing it should come as no surprise that self hypnosis is also highly effective at reducing pain.You can reduce or totally eliminate stress with very little effort.
The same goes with addictions and bad habbits...
So to sum it up, Hypnotism has found a place in medicine, psychology, entertainment and even dentistry. The benefits are-self-improvement, curing mental, emotional and physical ailments, controlling weight, past life regression, etc. Self-hypnosis is useful for certain problems, while others need hypnotherapy.
I would research about the subject give it a deep read or two if I were you... Hypnotherapy is something to read about as well in order to get deeply into the matter.