I agree that the design is a result of trading off the desire to do away with nulls vs retaining Java interoperability. Preventing (at compile time) only Option

I agree that the design is a result of trading off the desire to do away with nulls vs retaining Java interoperability. Preventing (at compile time) only Options from being null is surely impossible when casting/reflection are available. It is commonly understood that if an API returns Option[A] then the client can assume it will not return null. Personally I have never experienced a real error from this.