Did you actually read what I wrote? The full tracing property means that when double spending is detected, the bank can identify all coins that the cheating us

Did you actually read what I wrote? The full tracing property means that when double spending is detected, the bank can identify all coins that the cheating user spent. Honest users remain anonymous, which is the basic security property of ecash (and a property that Bitcoin does not achieve). Also, this may seem pedantic, but cheating is entirely feasible in Bitcoin. In Bitcoin the honest users must perform more computation than the attackers, but that means that an attack must be feasible (as the effort of honest users must be feasible for anyone to use the system).