Anonymous = Untraceable, for all parties (incl 3rd parties), who the senders and receivers of funds are. What amounts are being transferred and what those are for.

What is being discussed here is a hypothetical case.

First, it is assumed, that a flawless Anonymous Payment method exists. A method that truly works and that itself would not reveal any bits and pieces of the transaction nor the parties involved.

What exactly that payment method would be, whether likes bitcoins, credit cards, paypal, does not matter for the discussion. Thus this is written in a less direct way then "Bitcoins are good for the world", then a lot of the debate would be about the specifics of the Bitcoin implementation.

So what is being discussed here, is, explicitly, only the characteristic of anonymity of such a payment method. So whether such transactions or the ability to do such transactions, would be good for the world. Thus the formulation: "...anonymity, as a characteristic of such a system would be...."