My understanding was that Goldman Sachs will have that information and they will be responsible for fraud prevention etc. -- they just won't share it with Apple.
Their profit motive might save them. Or it could be a disaster, who knows. My guess is that Goldman would trade on the aggregate data
And then there's this, and a dozen other stories about Goldman Sachs deceiving its clients in the past.
https://www.washingtonpost.com/opinions/goldman-sachss-long-...
Typically it comes up in places where there's a question of whether the bank is responsible getting their client the best possible price in a transaction or whether the bank is acting as an arms-length counterparty who happens to be taking the other side of the transaction. It also depends on the sophistication of the client and whether it's a transaction where the client should expect Goldman to be bullshitting them.
Goldman acting as a bank for the Apple credit card is completely different from Goldman acting as the counterparty in a large FX hedge or bond deal.
Not that I like defending GS
It's hard to argue that Apple can keeps Goldman Sachs on a leash. GS can't get a worse reputation that it already has, shaming them is worthless.