I can't profess to be an expert andy, but as with most of these things, it's just another metaphor.
Basically it involves people using their imagination in a (hopefully) constructive way - hypnosis in other words.
As with all these 'named' approaches, the map is often mistaken for the territory. How many times have I heard "On my timeline..."
Personally, I am much more interested in simplifying psychology, not adding more names to make it more complex; but NLP has gone a bit the other way.