Lol. Funny, but idiotic if your goals are piracy.
I had similar ideas to be honest, but my goals were in creating an actual independent and entirely virtual country.
(Think second life but taken to whatever extreme technology allows)
The reason for having servers in international waters/airspace in such a case is that you can't run a truly independent nation from servers located within the territory of another country unless the other country happens to be cooperative.
Of course, the idea has more serious problems with regard to the citizens themselves; Since human beings can't be digitised (Not yet, in any event. And if it ever will be possible depends on a lot of unknowns to do with the nature of conciousness).
And since a human still has a body, you need actual land to put it on even if you have a country which otherwise is virtual.
At the bare minimum, you'd need space for a structure akin to how people's bodies are kept in the matrix plus the land needed to feed them.
Anyway, rather off-topic, but I just found it a funny coincidence that someone would want to try this with piracy...