Perhaps, however in the case of LNG export, there's also the...

Perhaps, however in the case of LNG export, there's also the issue of fugitive emissions throughout the supply chain from the North West Shelf to whereever the gas is being sent. While the hydrogen supply chain may have associated costs, so does the natural gas supply chain, and the hydrogen supply chain does not need to worry about fugitive emissions.

There are also other ways of exporting energy: As discussed here before, Australia could build new-age hydrogen-based iron ore proessing plants in the Pilbara to convert Pilbara iron ore into HBI briquettes using Pilbara natural gas that has been Hazered into H2 + graphite. The resulting HBI would essentually include a whole lot of imbedded green Australian energy that should be cheaper than green energy anywhere else in the world, and the cost of transporting HBI will be a lot less than transporting the iron ore containing the same amount of iron.