Buddha said "nowhere between the lowest of hells below and the highest heaven above, nowhere in all the infinite worlds that stretch right and left, is there the equal, much less the superior, of a Buddha. Incalculable is the excellence which springs from obeying the Precepts and from other virtuous conduct." - Apannaka Jataka
When the Buddha speaks of worlds he is talking about that in the world by which the world is perceived & conceived because that is what is called a world in that training.
There are many subjective frames of percepience by which the world is conceived and no two frames of perception are the same.
It is proven that there is no simultaneity of perceived events between observers (physics) and it helps to grasp this to appreciate the semantics of the dhamma and how each world is different from another.