Benefits of a USA Childbirth, Direct advantages to the parent
Parent can use US Citizens’ immigration line when traveling with the child
Child can sponsor the parents’ permanent residence in the future.
Financial aid for the kid’s college education in the US with no tax liability to the parent (assuming parents move back to China).
Furthermore, even when the kid is in college, he’ll find it easier to get internships, jobs etc.
I don’t see any downside here. Even if the Chinese government confiscates the kid’s US passport, that does not constitute loss of US citizenship.