OK, I agree that if spending 30 million brings in 31 million then it's a good deal. But firstly, I would say we have to be clear about the numbers; we know the cost is coming out of the public purse, how much money is made and who benefits is always a lot more complicated. For example, tourism exposure is notoriously difficult to calculate and often the figures given are by those with a vested interest.
Secondly, there is a opportunity cost. If we are looking to boost the technology sector would the money be better spend elsewhere? For example, a new internet cable linking NZ to the rest of the world.
Thirdly, the emotional argument runs both ways. Politicians love going to these kinds of events abroad or movie premiers at home, I hope that wouldn't a deciding factor but 'cool' industries often get a lot more government money than the uncool ones.