It's about intellectual honesty. It should be unambiguous what parts of a creative work are actually your creativity, and what parts are borrowed from others.

It's about intellectual honesty. It should be unambiguous what parts of a creative work are actually your creativity, and what parts are borrowed from others. Besides that, citations make a great way to pursue further reading. If an interesting idea gets mentioned in passing in an essay I'm reading, then if it's cited I can go read that other work. That's why you're supposed to cute your own works, when an idea in a given essay is just lifted from something else you wrote. I, as a reader, can then go check out that work, and in turn be lead to the ideas that helped shape that one by the citations in that work.