I’m migrating old ObservableObjects to the new Observation method with @Observable macro. What happens if I don’t mark the previously unpublished properties with @ObservationIgnored?

1. Would there be any meaningful performance/power penalties? Or any other complications like retaining references?
2. What if there is no observer objects/views observing that property? Would there be any difference in performance between annotating the property with @ObservationIgnored and not annotating at all?

Example:

original class:

class Class1: ObservableObject {
    @Published var a: Int = 1
    var b: Int = 2
}

new class:

@Observable class Class2 {
    var a: Int = 1
    var b: Int = 2 // Do I absolutely need to use @ObservationIgnored here?
}

Thank you!