The spirits are an age-old theme, a story from darkest history, and therefore a presentational anchor that can be used with many different magic tricks.
The house of magic has many rooms.
Magic teaches us how to lie without guilt.
Everyone wants to change, but no one wants to do anything differently.
All magic is about transformation... the performance magician is telling you that you are the magician in your own life. You are the agent of transformation, your own transformation.