Japan is particularly interesting because gaming in traditional consoles have been trending down for the last couple of years. In favor to mobile and portable approachs (see Switch succes). So if they played their cards right they might actually get a foothold in the country.
Mexico and Brazil are interesting because of the lower purchase power that the average citizen have. So a cheaper solution like XCloud might become popular there. That said the service will most likely only work on the capitals and other big cities that do have the infrastruture to suport it.
Australia is the one that I actually have no clue. Maybe it will help because of how expensive games are there and as they normally don’t have a local server for online play. The latency will most likely not bother them that much (same could be said about Brazil in that regard as well).