Most human beings are good at fantasizing ... some better than others.
One group which needs to hone their fantasizing skills are authors of works of fiction. The stark challenging white of the blank sheet of paper often tests the best authors.
Self-hypnosis enables creative people to tune straight into the most creative parts of their minds.
One of the criticisms of hypnosis when it has been used to obtain truth from people who have blocked out memories is that hypnosis does not unblock the memory but produces a new wrong memory. It is that fact which makes it so useful to would be authors and other artists.