Self hypnosis and meditation have different uses since meditation is a state in your mind and body is fully relaxed and you attain a thoughtless state.

Self hypnosis is used for healing and is perfomed by the person himself who wants to be healed. Hypnosis is used to provide affirmations of a positive nature to counter the issues the person is currently facing. For example a person has a stage fright issue. He will use affitmations and visualizations in a deep relaxed state to change this pattern. On routine and constant reaffirming a positive state where he is confident on speaking in front of the public this is deeply iingrained in the subconcious mind and the body will positively react while facing the public and the issue will be sorted out.

Self hypnosis is used to take the person into a deep relaxed state like meditation but after reaching this relaxed state person then uses commands to move to a positive healing state whereas in meditation it is a matter of letting go completely.. Hope this helps..