I went to CCB this morning, they'd never heard of it, said no problem. Good, because that's where my salary ends up.
Then I went to CMB and they seemed to know about "二代身份证明". They said my account didn't need it but they put my driver's licence on file anyway because it would make matters more convenient for me in the future.
I guess that foreigners may lose/change their passports some time and then get locked out of their accounts for good, and this is a way to mitigate this. But freezing their accounts if they fail to provide secondary ID is a bit harsh. I'm curious to find out more about this whole thing.