And when it it better than another event building, you can replace it.
Though I must say that some of the event buildings that offer a combi of pop and culture are sometimes tough to throw away for a high culture building. Some people are pretty much maxed out on their pop and doing so would prevent them from upgrading buildings.
Still, its a choice to make which is one of the ones I like about this game. And with all the changes going on, its one of the few points left.