In brief, worldbuilding is different than setting in my opinion. Setting is a room. A backdrop. It's scenery. But without good worldbuilding, you can't have realistic feeling scenery. You can't have cool, unique backdrops for your story.
Patrick RothfussFor me the really cool parts of being an author don't have anything to do with getting onto a bestseller list.
Patrick RothfussI grew up reading Tolkien, and I love him. But I love him in the way that you love that rambly old grandfather. You have to sit through some pretty off-topic stuff before he starts telling his cool old war stories.
Patrick Rothfuss