I think it's been released globally or at least on iOS it seem to be.
How many foreign travellers would even know they exist... like even if the foreign store thing was an issue I doubt many from outside Australia would even find it. On the first day of operations I asked the CEO about GDS integration and the response was along the lines of if it costs money then we're not going to do it.
That being said they're not totally invisible or 100% mobile like they want to make out. Here you can see it appearing on Skyscanner that points through to 4 different online travel agents - FlightNetwork, Mytrip, GotoGate and Trip.com (all owned by same people it seems). For reference this same date/flight is $129 on Bonza's website:
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Now doing some dummy bookings they offer one baggage add on and no seat selection which makes me think maybe these OTA's have no affiliation with Bonza and are actually just scraping the price once a day and pushing it up to their site, if/when someone books it they go and get someone to book it via app. I could be 100% wrong there but it does all seem a bit odd.