Quote from: toknormal on February 15, 2014, 11:31:58 AM

Quote from: toknormal on February 15, 2014, 01:50:26 AM

...if crypto ever gets near a coffee shop of supermarket, FORGET blockchain transactions. We will not be using 'real' cryptocurrency transactions for day to day purchases any more than banks use 'real' banks transfers for fiat transactions today. Even a 20 second confirmation time is 5 times to slow for point of sale purposes.

Quote from: Peter R on February 15, 2014, 02:22:44 AM

There's already a grocery store in Vancouver that accepts zero-confirm transactions. I doubt it's the only one in the world. We also have restaurants, pubs and coffee shops that accept zero-confirm on-chain transactions too. I already find paying with bitcoin less annoying than using my debit card.

That doesn't change the fact that blockchain transactions are not scaleable at the point of sale. If any physical retailer of any significant size (e.g. a supermarket) had to do blockchain transactions at the point of sale, their operations would grind to an immediate halt. It's just not going to happen. I develop e-Commerce systems for a living and payment processors are essential to scaling any kind of retail operation. Consider the following scenario:

[1] - you are in a supermarket queue with 30 items
[2] - the cashier rings through your items
[3] - they ask you if you want "cashback" with your sale and if you have a points card
[4] - you pay for the transaction, receive £50 (or $50) cash, which gets charged to your card account along with the groceries
[5] - as you pack your items, the guy behind you realises that the cashier accidentally rang through one one of his items on your side of belt splitter
[6] - the cashier discounts your sale, refunding you the excess balance and asks you if you want the refund in cash or refinded to your charge account
[7] - you leave the chop, having storecard points added, received your "cashback" amount in fiat, and having the corrected amount charged to your account

Now, there isn't a snowballs chance in hell of all that happening on the blockchain in realtime. It's not what the blockchain was designed for. This is what payment processors are for - they handle all this stuff effortlessly and provide added value to the retailer at the same time, for example by insuring the transaction, supporting auxiliary products such as discounts and store cards etc.

So don't have any illusions that Visa and Mastercard are going to loose any business to Bitcoin. They will be needed more than ever if cryptos take off (which I think they will). In fact they will actually be part of what drives the crypto economy and if we don't get them on our side then there will be no "gateway" for big retailers to come on board.

I was pointing out the fact that on-chain zero-confirm payments are already working in retail. PoS transactions are scalable, and many of the "features" you described can also be carried out on-chain with the appropriate payment processor. The transaction processing capabilities of bitcoin can scale greatly, even to Visa levels: https://en.bitcoin.it/wiki/Scalability. We will remove the 7 tps /1 Mbyte block-limit when required.

That being said, I agree that companies like Visa will continue to play an important role, by extending credit and offering consumer protections. And I also agree that in a "bitcoin future" more transactions would be done off-chain, and I gave an example of how Coinbase is already working towards this goal in an open and seamless manner.

The vision that I have is bitcoin PoS similar to how franky1 just described one post above: if you have a BitPay or Coinbase account, you pay super quickly via NFC at the till, off-chain transaction, no miner's fee. But if you don't have such an account, there will always be the option to pay "on chain" should that be required.