In that case, do you condsider Go's nil to not be a null, since you can call methods on it that can do whatever? Or how about objective C's nil, where any messages sent to it are simply ignored?

Edit: I see now that you're talking about the difference between null and Result/Option, not the difference between null/Option and Unit, so we're talking about different things.

Semantically, a value that could be data or null is equivalent to an option type. Option types have methods, yes, but that's just a superficial convenience facility, you could implement the same thing for nullable types by writing a function:

    public static <A, B> B map(A object, Function<A, B> f) {
        if (object == null) return null;
        return f.apply(object);
    }