I don't think about the 'land mass' being a requirement but they do have mass, but they are not recognized as a country. They claim to be recognized by the United Kingdom and what not but they actually aren't, and what's the point of being a king if you are only supposed to rule 50 people, and 1/5th of them already being your family. What's the point?
Probably just for the novelty value / attention they would get. Having your own island or country would be cool but not a crappy thing in the middle of the sea.