The Godzilla movies are lots of things, since the series likes to spice things up and go to unpredictable places, and also, there are just lots of Godzilla movies. If every single one of them involved the same version of Godzilla stomping around and eventually being defeated by humanity, things would get boring. In the interest of not being boring, he sometimes gets to be a hero, is sometimes a force of nature, and sometimes battles other giant monsters, instead of clashing more directly with the human race.