Well no one actually uses that status code... because there was no solution to guarantee that a digital payment is ever truly "done" until Bitcoin was invented.

I posted a link that people who are familiar with the development of the internet and HTTP will remember that there was a big problem back then.. we didn't have a digital native representation of value and all digital data structures can easily be copied so the fear of double-spends is what caused Digicash, Bitgold and a few other earlier digital currencies fail.

It's still a solution in search of a problem. In a marketplace, there are two fundamental fears to be addressed: the seller's fear that the customer will not pay the money for the goods, and the customer's fear that the seller will not actually provide the goods. The classic solution to this problem is escrow, where the seller and the customer both agree on a trusted third party who will hold the customer's money until the seller delivers the goods.

In modern times, credit cards and the like provide an adequate solution the problem (there's definitely strong dislike over things like fees, though). Early digital currencies failed because they weren't trustworthy as third parties, or they failed to gain a wide enough userbase to keep fees low. But it's not like they all failed--PayPal is with us today. Bitcoin and other cryptocurrencies suffer as a payment method in that they don't solve the customer's problem, particularly in cases like ransomware where there is strong reason to doubt the seller's ability to deliver.

I see it as an alternative to the current web tech stack that in my opinion isn't very secure and won't scale to match a machine-to-machine economy and that unfortunately can, and in some countries is used to monitor us.

> because there was no solution to guarantee that a digital payment is ever truly "done" until Bitcoin was invented.

Except blockchain based currency can't solve the "402 problem" as you call it. They are far to expensive and would never scale to the transaction volume required.

And if you are going to say "oh yeah well Lightning Network will save us!". Lightning Network is the biggest pile of vaporware I've ever heard of. It's been "just around the corner" to save bitcoin for almost as long as bitcoin has been a thing. ...I do love the solution to scaling the blockchain is to not use it--a real ringing endorsement of Satoshi's Glorious Block Chain if I ever heard one!

Which blockchain are you talking about? Most have probabilistic finality within seconds and CC transactions can take weeks to clear for the merchant.