Yes, it will be always an advantage for having multiple language for a platform like casino/gambling.
But if the platform only have particular target market, then having such feature (multiple language) doesn't make any sense so better to stick what they have considered.
Of course, it will be an advantage for casinos with multiple language features so that players from different countries can understand the features of the casino. As long as the platform releases its business on the internet, the business will develop better because it can get customers from different countries and its target market will also become bigger. And that means they need to be able to manage their site when they get a surge of customers playing on their site.