The effect is that your reader becomes immersed in the story, perceiving everything that your characters perceive as though they were really there.
What is storytelling without the show, don’t tell rule? “Show, don’t tell” is a way of using imagery to relay an experience to the reader, rather than spoon feeding that experience through literal description. The effect is that your reader becomes immersed in the story, perceiving everything that your characters perceive as though they were really there.