From my viewpoint, it smells fishy that with such an enormous amount of personal data for 1bil Chinese citizens, he only asks for 10 BTC.
Even giving out 750k data for verifying its legitimacy, I doubt anyone can make a cross-reference and verifying it except China govt. So again, 10 BTC for 1bil Chinese citizens data? If it was real then the 10 BTC price tag is just for show.
I think you forgot that he can resell the same data countless times. It is not blackmail, but a simple sale of illegally collected information on the black market. If he only has ten customers, that's already 100 Bitcoin!
I agree with this, I mean if we are selling 1 billion Chinese data for the very first time, you could even contact FBI or CIA or something and ask for a lot more, you could get rich. But if you already sold it like 100 times, then you could not ask that much, you just gotta drop the price a ton.
It is still 1 billion Chinese, so it is not going to be free or 100 bucks, but believe me as long as this exists eventually it will become free as well, you will see it shared everywhere eventually. My nation had a similar situation and now you can get it for free after 5 years. If this is real, the first one was probably expensive, now 10 btc, later it will be 1, and eventually free.