They do that in the UK too. It's been over-hyped, as with most stories about China.
I bought my last car "pre reg", meaning that the dealer bought it and registered the car in their name, and I bought it "second hand" with only a few kilometres on the clock. And when I got it, the dealer hadn't even bothered to register it to themselves, so I am the first and only owner.
It's just the way they discount new cars to fudge the numbers, very very common here. They can shift sales into different months, deal with over-stocking issues at storage locations, that kind of thing. Like all retail businesses, sometimes they need the throughput, sometimes they need the higher margin.