This article from Federal Reserve Bank of St. Loius, examines the relationship between payment systems and Priviacy.
Privacy in payments is desired not just for illegal transactions, but also for protection from malfeasance or negligence by counterparties or by the payments system provider itself. Proposals to abolish cash take inadequate account of these legitimate demands for privacy. While central banks can play a useful role in setting standards for payments privacy, they are unlikely to have a comparative advantage at providing privacy. Therefore the replacement of cash by central bank electronic money is likely to spur demand for alternative means of payments to solve specific privacy problems.