> For me, it is that I don't like all my purchases to be tracked in one giant database. That is one big reason, yes. A very important one. Aside from that, ca

> For me, it is that I don't like all my purchases to be tracked in one giant database. That is one big reason, yes. A very important one. Aside from that, cash is optimal in terms of dependencies. Namely, a cash transacion is solely between the only two parties that are relevant to the transaction, the buyer and the seller. Nothing can interfere or stop the payment if the buyer and seller agree if they use cash. All other payment types introduce third parties into the mix, all of whom can now block the transaction. So it adds risk. And the newer electronic payment types (like paypal, venmo etc, as opposed to credit cards) are even more sketchy. As HN knows from tons of submissions, they will not only block you on a whim but also steal any and all previous money you may have received. I'll never use any of those, the risk is way too high. Finally, there is also infrastructure risk. Even if the payment processor isn't trying to block your transaction or steal your money, the payment is dependent on all the infrastructure working correctly (server, their internet, your internet, your phone in many cases, etc). If anything is down, suddenly you can't pay anymore. While not super common, it is nonetheless relatively frequent around here to walk into a small shop where they have a sign saying "our internet is down, cash only today". So important to always have cash handy. The credit card cashback and buyer protections are attractive admittedly, so I end up using credit cards for anything larger but try to generally always use cash for anything under $100 for all the benefits of cash. As any engineer knows, every additional moving part dependency you add to a system also adds risk of failure. Cash has zero external dependencies so it is optimally resilient.