How to Update a UILabel Object with MainActor

I guess I was in coma, and I didn't learn of MainActor till today.

So I have the following lines of code to test MainActor.

import UIKit

class ViewController: UIViewController {
	// MARK: - IBOutlet
	@IBOutlet weak var label: UILabel!
	
	
	// MARK: - IBAction
	@IBAction func buttonTapped(_ sender: UIButton) {
		Task {
			do {
				let bool = try await asyncWaitMakeLabelChanges()
				if bool {
					print("I'm done!")
				}
			} catch {
				print("\(error.localizedDescription)")
			}
		}
	}

	func asyncWaitMakeLabelChanges() async throws -> Bool {
		for i in 0..<5 {
			let text = String(i)
			label.text = text // UILabel.text must be used from main thread only
			print(text)
			sleep(1)
		}
		return true
	}
}

As I expect, I get the purple main thread checker error at the line where I update the label. That's good. And I've changed the code as follows.

import UIKit

class ViewController: UIViewController {
	// MARK: - IBOutlet
	@IBOutlet weak var label: UILabel!
	
	
	// MARK: - IBAction
	@IBAction func buttonTapped(_ sender: UIButton) {
		Task {
			do {
				let bool = try await asyncWaitMakeLabelChanges()
				if bool {
					print("I'm done!")
				}
			} catch {
				print("\(error.localizedDescription)")
			}
		}
	}

	func asyncWaitMakeLabelChanges() async throws -> Bool {
		for i in 0..<5 {
			let text = String(i)
			Task { @MainActor in
				label.text = text
			}
			print(text)
			sleep(1)
		}
		return true
	}
}

Okay. The app won't crash. But the label won't get updated every second. It will finally display the number (4) when the count reaches 4. So my question is why not?

I could change my code as follows to update my label every second.

	func asyncWaitMakeLabelChanges() async throws -> Bool {
		for i in 0..<5 {
			let text = String(i)
			DispatchQueue.main.async() { [weak self] in
				self?.label.text = text
			}
			print(text)
			sleep(1)
		}
		return true
	}

So why would I want to use MainActor?