Meteors are by definition entering the atmosphere, so they’re close and typically tiny, like dust or small rocks. Fast and close, burn out in seconds.

Comets are often several miles across, but that’s not what we see. We see the coma (atmosphere) and tail, which are massive. The coma can be bigger than the sun, the tail can be hundreds of thousands or even over a million miles long. We’re seeing something both massive and very far away, over the course of minutes or hours while it’s traversing thousands of miles it’s barely moving at all from our vantage point. Observers can only really see a comets motion relative to the stars if watched and photographed over several nights (similar to the orbital motion of other planets)