Basically, if they will develop a blockchain project that is considerably decentralized, it doesn't matter if they are a communist country. People will still believe and support them as long as they are always updating and developing their technology. In terms of the adoption of China, the impact is massive especially to people who know how big China is. Their population is already an advertisement for others to adopt to cryptocurrency especially investors. As the mindset of most investors is like this: They will do their best to see what will happen in the future, so they will look at possibilities and Chinese involvement will set as an initiative for them to have a reason to invest in cryptocurrency.
It's important to note that China is excited about
Blockchain, not cryptocurrencies. It was not obvious from the initial president's statement whether they are distinguished by the government, but I remember reading a clarification later that it's about Blockchain, not about approving of these speculative cryptocurrencies we have nowadays (although I cannot find that article right now...). If that's the case, then China might use Blockchain for various purposes and perhaps even make their own crypto, but not boost the adoption of the actual cryptos like Bitcoin.