That is null as a reference. Null as a type, however, is useful. An off the top of the head situation is suppose you have a ballot. On this ballot, one can vote

That is null as a reference. Null as a type, however, is useful. An off the top of the head situation is suppose you have a ballot. On this ballot, one can vote for one of x, or they can choose to not vote for any at all. In verifying and tabulating the votes, having a null value makes a lot of the rest of the process easier.