[ryanlol]

Edited the comment to include verification almost simultaneously with your post :)

But yeah, obviously as the transaction value goes up the merchant will need to wait a few more seconds to counter doublespend attacks.

>You must submit it to the network

Not necessarily true, ideally the customer doesn't need internet connection and just transmits the signed transaction to the PoS.

>and the merchant must be reasonably confident that it will be accepted in a block as-is and that the block will not be orphaned

First of which can be verified very fast by a computer. I believe orphaned blocks are rare enough that they're mostly a non-issue.

I guess it's important to point out that in practice most Bitcoin ATMs I've used did 0-confirmation transactions up to 1000 euros after only a few second wait, so it's not like all bitcoin merchants suck.

[ceejayoz]

The average confirmation time for a Bitcoin transaction was 400+ minutes recently (and is still around an hour even now). https://blockchain.info/charts/avg-confirmation-time?daysAve...

[ryanlol]

Yes, but you don't need more than 20-30 seconds to be confident that a transaction isn't a doublespend attempt.

After that it's only about checking if the fee is high enough.

[ceejayoz]

> After that it's only about checking if the fee is high enough.

Which can take up to 72 hours, right?

[ryanlol]

No, you just check if the fee per KB is more than x. Where x is a fee that is likely enough to confirm. This is practically instant.

[ceejayoz]

I'm not sure "likely enough to confirm" is going to go over all that well with many merchants, particularly when that chart shows the price-per-byte jumps all over the place rapidly.