What does it mean to turn China concept stock into a major listing?

Recently, BiliBili $Bilibili(BILI.US)$ and Alibaba $Alibaba(BABA.US)$ have announced that they will convert their application for secondary listing on the Hong Kong Stock Exchange into the main listing status, which is expected to take effect in October 2022 and the end of the year, respectively.
Prior to this, the SEC of the securities and Exchange Commission of the United States included four companies including Alibaba in the pre identified list with potential delisting risks.
CICC $CICC(03908.HK)$ pointed out that turning into a major listing can get rid of the impact of changes in external listing status, and the trading and convertibility of Hong Kong stocks themselves will not be affected. They can be included in the Shanghai Hong Kong Stock Connect, thereby increasing liquidity. $China Concept Stocks(BK2517.US)$