Sometimes it's just the culture of the people. You can see that they are willing to take the risk on the expense of ending up with nothing. It's not just the casino but it's pretty inherent with stock markets as well. When it comes to bitcoin, for them it's just an opportunity to gamble and make more money. I don't know if technology means that much to them, but the allure of profit would be the main driver.
Financial repression by the Chinese government is another reason. With interest rates kept artificially low, people are forced to look for alternative assets where the yield is higher. So the stock markets turn out to be a gamble, which the Chinese take.