What are the benefits of using short sentences in writing stories or novels? Why might an author choose to use shorter sentences instead of longer ones?

Short sentences are punchy. They are read quickly. In dialogue they move fast.

Short sentences force writers to choose words carefully.

To be concise you must be precise.

Short sentences favour the concrete over the abstract.

If you are writing about philosophical or metaphorical matters, both the language and the content will probably require longer more convoluted sentences structures to capture the layers of overlapping meaning which are not easily segregated by a full stop