在下面的片段中，Xcode推荐“使用#selector而不是显式构造一个选择器”的原因是什么？

// addButton = UIBarButtonItem.init(barButtonSystemItem: UIBarButtonSystemItem.Add, 
//             target: self, action: #selector(FoldersMaintenanceVC.addButtonPressed))
addButton = UIBarButtonItem.init(barButtonSystemItem: UIBarButtonSystemItem.Add, 
            target: self, action: Selector("addButtonPressed"))

self.navigationItem.leftBarButtonItem = addButton

func addButtonPressed()
{
    myNslogSys2(self, funcName:#function)
}