What's the point of a 'fast' coin ?

Hi Folks

I am a professional eCommerce systems developer and this is something that has been bothering me for a while regarding coins which are promoted as being "fast".

The only advantage I can see of a coin having fast transaction times is for use at POS (Point of Sale) terminals. However, if cryptocurrencies ever get near supermarket checkouts, I think it's very unlikely that people will be doing actual blockchain transactions right at the checkout.

What's likely to happen is that transaction clearing houses like Visa and Maestro will handle the transaction at the point of sale and then carry out the actual "underlying" money (in this case blockchain) transaction as they do today.

What people need to understand is that there is a whole industrial layer *on top* of the real money system which takes care of buffering the waiting time away from the customer at the point of sale. That "clearing house" layer also has time to resolve problems like the occasional delay etc.

You can see this today - when you pay for your supermarket goods and leave the place, the transaction won't show up in your bank account for a while. That's because the supermarket POS systems are not actually doing the money transfer - only sending a number to a server which instructs the clearing house to debit an account. This process is extremely fast. It also allows for problem resolution without bothering the customer. cryptocurrencies are never going to get near this level of "smoothness" and performance because crypto's are doing everything at once - they are both handling the point of sale support AND doing the underlying money transfer.

So my thinking is that there's very little advantage in pushing transaction times for "cryptos" below the level of a few minutes because they're not going to be manifesting themselves at the point of sale anyway. That "clearing house" layer is always going to be needed.

What I think is that there are 2 optimal transaction times for "cryptos"

[1] - sub 5 minutes is very good because it competes well with banks doing "real" money transfers. It's also a reasonable waiting time for email confirmations for internet transactions.

[2] - sub 1 minute MAY be good for certain limited things like buying a train ticket at a station platform

[3] - pushing it further than that is a waste of time. POS is never going ot be doing direct blockchain interaction. Even 30 seconds is far to long for a supermarket queue and the vendor is exposing themselves to far too much risk in having to support the full underlying money transfer

So I think coins, having got the transaction times down to sub 5-minute, should just forget about performance and concentrate on socio-economic issues (like distribution) and reliability.

Pete