^ This reason has made sense to me and it is definitely right.
If a gambling casino platform is pure Chinese language use it will probably be that they are focused on their local not on the international
More like, focusing in chinese people who resides outside china and the business is based outside china too. Coz if the platform is accepting crypto then they are subject to be seized by their government knowing china hate crypto. So focusing only to their locals and operating in the country doesn't make any sense.
Also, probably the team behind only knows chinese language making more sense.
But it would be better to use multiple languages for their site so people who don't understand Chinese can see the gambling games. It can also attract people who want a new experience with Chinese-style gambling games. In addition, they can have the opportunity to have members from outside China and develop their site even more. Or maybe the casino team just wants to use Chinese and doesn't want to get into trouble if they use multiple languages.