As mentioned in comment you replied too, both cash withdrawals & deposits are scanned — and most cash is only used once between receipt and being spent before entering banks again. For small volume of cash, might be possible to remain anonymous, but for large volumes, it would be extremely hard without there being a cost to doing so and might even be technically money laundering, which is illegal. Most retail locations will not break bills without transactions and will not take unusually large bills for transactions. When combined with other methods of surveillance, such as asset tracking, location-data, security cameras, etc, it’s virtually impossible to stay anonymous at any significant scale.

Core point is like blockchain, people do not realize how traceable cash is and many falsely assume it’s completely anonymous, which it is not.