LLMs can do chat-completion, they don't do only chat completion. There are LLMs for image generation, voice generation, video generation and possibly more. The camera of a drone inputs images for the LLM, then it determines what action take based on that. Similar to if you asked ChatGPT "there is a tree in this picture, if you were operating a drone, what action would you take to avoid collision", except the "there is a tree" part is done by the LLMs image recognition, and the sys prompt is "recognize objects and avoid collision", of course I'm simplifying it a lot but it is essentially generating navigational directions under a visual context using image recognition.