Why does ShapeEdit use FileManager copyItem instead of setUbiquitous?

I have a question about code in the ShapeEdit sample from Apple.

I their code, as shown below, why did they use FileManager's copyItem method instead of its setUbiquitous method? Didn't the documentation say explicitly to use setUbiquitous method?

            NSFileCoordinator().coordinate(with: [readIntent, writeIntent], queue: self.coordinationQueue) { error in
                if error != nil {
                    return
                }
                
                do {
                    try fileManager.copyItem(at: readIntent.url, to: writeIntent.url)
                    
                    try (writeIntent.url as NSURL).setResourceValue(true, forKey: URLResourceKey.hasHiddenExtensionKey)
                    
                    OperationQueue.main.addOperation {
                        self.openDocumentAtURL(writeIntent.url)
                    }
                }
                catch {
                    fatalError("Unexpected error during trivial file operations: \(error)")
                }
            }