The US is unique in that it views these firms as unlicensed and illegal (despite their having licenses in other jurisdictions). Surely your Australian online casinos are ok or are they not licensed by Australia? I don't know about casinos, but I know the sports firms there are licensed in Australia and so there would be no issue hosting your website there. From a performance and
seo viewpoint you are best off hosting in the target country, but this sure highlights the need to work out what alternatives you would use were your sites to be suspended.