>Cryptocurrencies, except BTC and a couple of others, are doing it right. A transfer should cost a fraction of a cent.

Most people would prefer to not be out all their life savings if someone swipes their card number. Combating and refunding fraudulent transactions takes some cost.

Well, that's kind of an unfair strawman. Cryptocurrencies are best used as transactional currency instruments to buy with local cash and then immediately exchange for goods/services, rather than savings currencies to hide money in, risking high-beta loses from day-to-day.

What would be superior is if every nation's national post office provided basic banking, debit card and mobile payment services for free (think similar to China's amazing system), so that no one would have to be unbanked except by choice. If people are in the "gubberment shouldn't exist" camp, then there should be a trans-national, independent, non-profit credit card system that provides credit card processing and transfer of money at about the cost of delivery: no surprises and no exploiting a basic human need to hand over as much cash as possible to short-term interested stock speculators.

In the EU, you have a right to a basic bank account including a payment card and online banking.

In terms of developed countries, again, the US is an outlier in its treatment of people with no good options.

Bank transfers in Europe are now typically free. Cards expose the bank to a certain (small) degree of risk Nd administrative cost, so they’d probably stop offering the service if rates were regulated to zero.

But unlike bitcoin, visa doesn’t create an enormous carbon footprint every time somebody buys a pack of gum at a gas station.

Every time you Google something, you create an enormous carbon footprint. Every time you drive. Every time you eat. Every time you watch a movie.

I'm out of the loop on this stuff, but are others doing things to prevent the situation Bitcoin had a couple years ago, when it hit $37 per transaction?

That seemed to happen due to a massive price and volume increase, so is hard to design for. At the same time, at peak, it was still doing a tiny fraction of the volume that any of the credit card networks do.

Blockchain scaling is still a very active area of research, and anyone (like GP) telling you there's a battle-tested solution available today to replace Visa is lying to you.

On the precise issue of transaction cost predictability, I think most solutions would revolve around creating a market for the ability to execute future transactions. There's a hackish project on Ethereum doing just that: https://gastoken.io/

Do crypto currencies have fraud protections like credit cards and debit cards?