Using any of the network sites should feel very similar for any seasoned iNaturalist user since it’s all hte same community, database, and software. The key benefits for the everyday user are be a more localized experience (as noted by others above) and the support of local organizations. The additional benefit for research and conservation is that Network member organizations (such as ALA in this case) can also access automatically hidden coordinates due to taxon geoprivacy within their country.
If you look in your account settings, you can choose to affiliate your iNaturalist account with iNaturalist Australia (and keep signing in on whichever site you choose), which additionally provides access to coordinates you have personally chose to make obscured or private. If you keep your affiliation as iNaturalist.org, coordinates hidden due to your geoprivacy selections are never shared with other groups (aside from any selections you may have made for traditional projects or user-to-user trust).
