Cheaper tech teams with less competition. Australia has a lot of talent in the software space, but without the eye watering wage bills. Even in the most expensive cities of Sydney and Melbourne, software developers generally cost a lot less than in the Bay Area. You can get even better value if you can build your team outside of Sydney/Melbourne.
You can build more slowly, there is alot less pressure to build grow fast and fail type startups. While venture capital heavy startups are the most celebrated in the press, there are plenty of great smaller scale self/revenue funded startups that can build up over time. Most of our celebrated tech successes built their business models over a long time and focused on building a good business first.
There are also great incentives to keep the development team in Australia. As a pre revenue startup you can get over 43.5% of your development cost back through the R&D Tax Incentive. While its a tax incentive, the way that they designed it was to provide tax refunds to loss making companies. Plus there are other great grants/incentives you can also take advantage of. (disclaimer: I'm a consultant for software startups/companies in this area)
The best course of action is to take a global approach, don't limit yourself to selling or developing in only one location.