[ianmiers]

Paying in cash, in addition to being a minor inconvenience that non-the-less outweighs most people's desire for privacy, does not work in online payments. It also doesn't work in businesses that get robbed.

The better question is, why do you need a new currency to get privacy? Why couldn't we have a private crypto currency backed by dollars or euros? There's no technical reason, indeed several groups are building this. What remains to be seen is if there's sufficient incentives to build anything around these or for any portion of the economy to move to them. Most purchases aren't sensitive, so for private payments to work, they need to be ubiquitous for non privacy reasons and just give people who need it the option for privacy. Much like cash does. But again, cash doesn't work online or increasingly offline

[ETH_start]

>>Why couldn't we have a private crypto currency backed by dollars or euros?

Yes, you can utilize dollar backed and dollar pegged stablecoins, like USDC and DAI, respectively, in privacy-shielding protocols like https://zk.money and https://tornado.cash.

The problem at the moment is that Ethereum has very limited scalability, and privacy-shielded transactions are about five to ten times more compute-intensive than vanilla transactions, making them prohibitively expensive to conduct for most applications.

Ethereum layer 2 solutions that preserve the base layer's decentralization hold the promise to make such transactions viable at scale, but they are still quite immature in their feature set. For example, all of the general computation L2s still rely on a centralized coordinator.

[genev]

> Why couldn't we have a private crypto currency backed by dollars or euros? There's no technical reason, indeed several groups are building this.

That's what Monero is, right? It doesn't really matter how stable it is, if I'm just going to convert to USD/EUR immediately after my transaction.

[bowsamic]

No, Monero is not pegged to any other currency

[ev1]

> Paying in cash, in addition to being a minor inconvenience that non-the-less outweighs most people's desire for privacy, does not work in online payments

In some countries it's fairly popular and super common with kids to check out, get a barcode/receipt and pay at, for example, a 7-11 with cash for in game purchase top ups.

[Akronymus]

Ah, that takes me right back to adolesence. Getting a paysafecard in the morning near the school from a tobacco shop to redeem it in the evening at home.