Arrival is a melancholy movie, very deliberately built out of paradoxes: fear commissions the operation of reason. Violence induces compassion. Visitors arrive without traveling. Hope exists in the sure knowledge of tragedy. Being a piece of art, it expresses these paradoxes with particular symbols, from the lexical to the musical to the visual idiom that we’re used to in the movies around us. And being a piece of science fiction, it’s concerned with the world of the creators far more than with the world of the fiction, which serves as an extended metaphor for the human experience.
First contact stories, with their inherent and explicit contact with The Other, approach the Platonic ideal of Science Fiction. They highlight what we think is true about ourselves (for whatever value of “ourselves” the author cares about) and contrast it with an alien that possesses a critical difference in that dimension. Through the meeting of “us” and “them”, the author then gets to make an assertion about the society in which they live, for better and worse, and then get to stretch their imagination to do all the really fun, skiffy stuff, like determining how their aliens’ different physiological needs presents them with different cultural options.