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.
That is true, China donkit accept cryptocurrencies, it is illegal in China. But not only cryptocurrencies are not accepted in China, also gambling is also not accepted and banned. It may be possible that gambling has been alliweed in China in the past, I do not know, but gambling is no more acceptable in China and is banned. So what you are saying is right, the gambling site woukd only be targeting only the Chinese tht are not residing in China, but it is very possible that some Chinese that are living in China to illegally use such gambling site.