After the introduction of stock index futures, the spot t+ 1 is very unsuitable and cannot hedge the risk.
China's spot trading system is also implemented in two ways. t+0 is implemented for large institutions, because short selling is t+0, and etf index funds can also be converted into a basket of stocks on the same day, which is also a substantial t+0. But for retail investors, the implementation is t+ 1. Doing so violates the principle of "three publics", which is a violation of the securities law and is illegal.
T+0 can restrain excessive speculation. This has been proved by almost all foreign stock markets. Practice is the only criterion for testing truth. Some people deliberately reverse black and white, saying that t+0 will increase speculation, with ulterior motives.