The traditional financial system has coasted along on having two different sets of rules - one for consumer-facing things where you can do whatever you want with anonymous cash up to a certain amount, and one for Big Serious Transactions. The distinction between those two regimes is breaking down, and I don't want to see consumer privacy get left behind. Thus it's appropriate to reason from first principles about what ought to be, and not simply what regulations law enforcement has been able to get pushed through to make their own jobs easier. Individuals should not have everything we purchase be permanently recorded in order to convince us to buy more crap or price discriminate or whatever. Financial privacy is a key part of that.