in basic terms, raster and vector are two different types of images. raster is used for more detailed works, while vector is used for more basic images. vector, because of the complexity, suffers from pixel degredation, which is why we get this nice ombre. you cant do this with the new editor, because it uses vector. this is an extremely basic explanation, and doesn't really explain why. hope this is informative!

it lowkey is tho the only reason i know this is bc flash used vector, and this youtuber i watch made a vid abt this oldish flash cartoon abt wrestlers and the hd looked real smooth