Firstly, the Opera House has obviously not been designed as a billboard.
Secondly, as a resident of a city which has a public holiday for a horse race (and now for AFL Grand Final as well) I'm not sure I'm in too good a position to criticise the horse-racing practices of other cities.
Thirdly, I am definitely not in favour of certain news organisations holding a disproportionate political influence. Theoretically the fourth estate were supposed to be the power that held otherwise unaccountable politicians to account, not the ones who said what those politicians should do.
Finally, those numbers! For a start, I don't think economic impact is the only way to determine the value of a proposal. But, even if it were, the $100 million is completely irrelevant, unless Jones is suggesting that without the Opera House advertising it will bring in $0. All that matters is additional income as a result of that advertising. And personally, I assume that it won't make much difference: if it's a big enough event, it's unlikely that lighting up the Opera House will bring it to the attention of many people who didn't already know about it
and will be interested in it. But then there's the counter-number:
this article says Deloitte in 2014 valued the Opera House as worth $775 million / year to the Australian economy (it is pretty iconic...). What's the risk of affecting that? Now I'm no more suggesting that the advertising will lose the economy $775 million than that it will gain the economy $100 million. But even in economic terms it's a questionable decision -
and we shouldn't judge such decisions solely on economic terms anyway.
(Ideally we wouldn't judge such decisions solely on political cost either...)