I don't think that's correct. Every East Asian country that has adopted the Japanese export model, including China, has pegged its currency to the dollar, with dirty floats being the rule. It's mooted as a way of keeping costs for domestic and foreign investors predictable, and preventing a rapid escalation in local costs. Has it been beneficial for their economies? I can't really tell, because every one of them has done more or less the same thing. I suspect this is because everyone of them knows that what came out of the Japanese economic sausage machine tastes good, but nobody knows which sausage ingredient can be left out and still produce equally good results.
Rates paid on deposits in China are effectively negative. It is why some invest their money in America.
Has it been beneficial for their economies?
The game has diluted because there isn't the buying power left in America to fund it. We have exported our wealth, not just in cash, but mostly in manufacturing technology that is now collecting unemployment, social security, and food stamps.