Nullable enum or an additional element

Question

Consider the following Enum and a corrsponding nullable field of that type

enum PossibleOptions { One, Two }

PossibleOptions? option;

Alternatively I could declare the enum and the corresponding field as

enum PossibleOptions { Unspecified, One, Two }

PossibleOptions option;

This non-nullable field would be initialized to the first value i.e 'Unspecified' and I achieve the same result as a nullable ('Unspecified' would replace option.HasValue).

Why go for a Nullable then? Any performance gains or other advantages?

Answer 1

I know you are asking about reasons in favor of nullable enums, but personally I don't see any reason to use them.

An enum that has an "invalid" member is in my opinion a lot more readable and conveys meaning much more than a nullable.