在iOS中，将视图添加为子视图与将视图分配给视图属性有区别吗？

let parentView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
let childLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 50))
parentView.addSubview(childLabel)

class ViewController: UIViewController {
    let label = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 50))
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view = label
    }
}