String s = null; That's not possible with nullable types. The whole point of nullable types is to mark types that can be null. So this is possible: String

String s = null; That's not possible with nullable types. The whole point of nullable types is to mark types that can be null. So this is possible: String? s = null; But now it's not much different than this: Option<String> s = None; My point is that these are fundamentally the same thing. The only difference is syntax, ergonomics, and compiler support.