Hypnotic phenomena is an interesting topic. Watching or experiencing the phenomena being elicited can be exciting. Imagine, the hypnotist tells you to extend your arm, and then tells you that it is stiff as a board. Low and behold, your arm is locked at the elbow ans you are not able to bend it or to put it down.
Unfortunately stage hypnotists use these hypnotic phenomena to make it look like they have power over the subject, which they do not. But many people think they do, and this leads to a lot of misconceptions about hypnosis.
Unless we are talking about the elimination of severe pain, or the retrieval of deeply suppressed memories, depth of trance does not matter!