Why is Rentvest using one of the government funding schemes? 

Rentvesting is ok because it's affordable. And that's what's important because it's affordable. 

You may get a first-time buyer's grant, but where are you going to be living? You're probably going to have to be living one and a half hours' drive from Sydney or in other parts of Melbourne, etc., or even Brisbane. So there's nothing wrong with Rentvesting. If it's going to allow you to get ahead, save your laundry payments, be close to community schools, get to your job easily, and then put money aside eventually by purchasing investment properties instead, you could sell those properties and then go buy your own home, rather than taking a massive mortgage that you can't afford to repay and struggling to make ends meet.