Symbolism in films is used to convey deeper meanings. It allows filmmakers to emphasize themes on a metaphorical level. It often provides visual and emotional depth to the story by representing abstract and intangible concepts in a visual manner. There are various ways it can be used, sometimes to deepen the understanding of the character or as a representation of their inner journey, or to hint at future developments or summarize the overall narrative.
Symbolism often provides subtextual commentary, allowing filmmakers to subtly communicate messages.
But it is important not to confuse it with motif, which is a recurring element in the film. Symbolism is often singular instances with deeper meaning. Although both are used to enhance the thematic values, symbolism is a more metaphorical reference that goes beyond literal interpretation.