Ok, I am totally not following this.
You buy bonds, which is basically you invest some money that someone else uses.
Periodically there is some kind of a lottery where if your bond's number comes up, you win a prize. But you are by no means absolutely going to win.
When you cash-out more than you paid in, you owe (if you are a US citizen) taxes to the USA, right?
So....it's like a lottery that doesn't make you any income unless you win a "prize"?