Well, if you use credit cards that data gets tracked, stored, mined for years to come, not to mention the dozens of internet servers it took for you to buy that bread in the immediate. If you use cash, I'd assume some local authorities use extra AI to track your movements via cloud cameras (plus fiat isn't fungible since it has serial numbers)
It would be nice to hear the "pro-[insert your local fiat]" energy use when people argue environmentalism against cryptocurrencies