This will probably be “good” for China in the long run of 50-100 years down the line but it’s the exact opposite of what humans should be. It’s going to be a disgusting seething horde of Han Chinese, standardized, of common think and purpose, arrogant to everything they have lost. All of this for what? A slightly higher standard of living? Less opposition to the party? What a waste of a beautiful culture and millennia of history.
How will this be good for the country?
Standardized, no opposition to the government, docile population etc. that’s why “good” is in quotations. It’s definitely not objectively good.
It may seem whataboutism, but really France does not seems to have got much bad press for turning their linguistically/culturally diverse country into a French speaking monoculture.