I'm not the OP, but I think I can see what he means, and I think he means it in a non-pejorative way too.

One of the functions of banks is indeed to hide the source and destination of your money. My grocer doesn't get to know who employs me; my employer doesn't see where I spend my money.

Yes, you can achieve that with cash, without directly involving a bank. But the money is still issued by a bank.

I'm not saying that it's impossible to achieve this level of information hiding without banks, but I can see where the GP is coming from in his argument.

I suppose that was a throwaway quip directed at HSBC who seems to have managed to get away with laundering on a large scale with some slapped wrists.