In the UK, they've taken some tills out. About 4 tills become 16 self checkouts. They still have plenty of tills for normal checkout.
It definitely lets less staff get more people through, in less time. So far, it's not been excessively abused over here. It's also made my life significantly less annoying.
I've got an unsubstantiated theory. China got fed up with the rest of the world bickering about how to combat climate change. Instead they asked where they could get most bang for their buck independently?
Flooding the world with cheap solar panels and cheap electric cars looks like a highly cost efficient method.