Recently, a lot of exchanges have been promoting U.S. stocks.

Mainland A-share users very rarely make other trading choices.
Hitting the daily limit up 10 times and the daily limit down 10 times every day is already enough for them to play with.
At most, they just watch from the sidelines—once the U.S. market really goes through daily limit-down of ten boards, you’ll see what they turn into.
Unless the “get rich” myth spreads more, maybe they’ll come in and try their luck, with gains and losses on their own account.
I think most of it is because crypto liquidity is now a bit weak, or because the market is simply too bearish, so they switched over.