Australia is a proving ground, not the market
The first market is chosen for the quality of the test it produces, not for the size of the prize it contains.
One destination institution operating under a profile, and paying for it, at arm's length. Everything else is preparation.
Why the first market is Australia
Australian agriculture already carries current, not anticipated, evidence pain: export-facing buyer requirements, environmental and biosecurity reporting, and financing relationships that all demand evidence from systems that were never built to share it.
The market is also small enough to reach real destination institutions directly, and heterogeneous enough that a contract which survives it is unlikely to be an artefact of one commodity.
What Australia is being used to prove
Three things: that the pain is real and current; that a narrow contract survives materially different Australian source systems; and that at least one destination institution will operate under a profile and pay for it.
Australia is a proving ground, not the addressable market. The venture case depends on the same contract crossing borders later while authority stays local.
What would falsify the first-market choice
If Australian destinations turn out to accept unstructured attestations indefinitely, the pain is not yet expensive enough and the sequencing is wrong.
If evidence that works in Australia cannot cross into a second jurisdiction without redesigning the core, the portability claim fails at the point that matters most.