How should I use UIConfigurationStateCustomKey?

Hi!

Beginning

I would like to know about UIConfigurationStateCustomKey.

Documentation

In a documentation we can find example where CellConfiguration has been extended and later CustomCell subclass get a property to update cell if needed.

A part of documentation:

Code Block 
// Declare a custom key for a custom isArchived state. 
extension UIConfigurationStateCustomKey {
    static let isArchived = UIConfigurationStateCustomKey("com.my-app.MyCell.isArchived")
}
// Declare an extension on the cell state structure to provide a typed property for this custom state.
extension UICellConfigurationState {
    var isArchived: Bool {
        get { return self[.isArchived] as? Bool ?? false } 
        set { self[.isArchived] = newValue }
    }
}
class MyCell: UICollectionViewCell {
    // This is an existing custom property of the cell.
    var isArchived: Bool { 
        didSet {
            // Ensure that an update is performed whenever this property changes.
            if oldValue != isArchived { 
                setNeedsUpdateConfiguration()
            }
        }
    }
}

Documentation example

Look at it carefully. We define custom key and, later, add stored property to ConfigurationState.
But!
We also define a property for MyCell, which has didSet hook with setNeedsUpdateConfiguration invocation.

How do I understand this pattern?

We define a custom property that could be stored in cell configuration.
Later, that property can be changed by a user. So, whenever something happened ( user press a button? ), this cell object receives obj.isArchived = valueFromUser.

But!

If we use this approach, we also define UIContentConfiguration with our UIContentView. That means, that we have our CustomUIContentView: UIContentView with all buttons that we need.
These buttons change state of an associated model object.
So, we define Row with all booleans which are related/mapped to buttons on CustomUIContentView.

Conclusion

There is no point where we should use properties for Cells.

Question

Am I missing something with new API?