Android @Immutable 对数据类有什么好处

看一下documentation of Immutable，这里有一个代码示例:

@Immutable
data class Person(val name: String, val phoneNumber: String)

@Composable
fun PersonView(person: Person) {
    Column {
        Row {
            Text("Name: ")
            Text(person.name)
        }
        Row {
            Text("Phone: ")
            Text(person.phoneNumber)
        }
    }
}

@Composable
fun PeopleView(people: List<Person>) {
    Column {
        for (person in people) {
            PersonView(person)
        }
    }
}

还有一段文字:

标记Person不可变允许跳过对PersonView Composable函数的调用，如果它是与上次合成时相同的Person.

我的问题是:

If recomposition occurs only when arguments of @Composable function change and data classes like Person in the code above (i.e. containing only primitive vals) cannot be changed without creating a new instance, then what's the optimization here?
When would the calls to the PersonView Composable function be skipped compared to the same code but without the @Immutable annotation? Is it somehow related to the mutable/unstable argument people: List<Person> of PeopleView?