not everyone needs a hooker dogma but everyone does need a place to live. I guess the government's trying to help a lot of people rather than a few blokes that can't pickup.
government (tax payers) inject $7k to help a sale for first time buyer, say at $500k sell price, then get more than double back from stamp duty, possibly capital gains, and GST on some of those services listed where applicable to each sale. It's a good bet.
But government gets nothing if property sales aren't occuring. So rather than raise taxes they're having a crack at doing it this way first.