> giver and receiver perfectly "identified" (in a unique way, albeit just pseudonymous)

Not perfectly. A lot of heuristics are needed to link a unique owner to multiple transactions. With bitcoin, it's recommended to use a new address for every transaction so, for example, in a basic transaction, it's not so easy to identify which output is the recipient and which is the change.

And there's Monero that tries to hide these links a lot more.