[jcranmer]

This is somewhat disingenuous. Transaction times can be as low as 10 minutes on Bitcoin, but this has high volatility. If I look in the past few months, average transaction times spike to a few hours quite frequently. Of course, if you look at the graph for January, the average transaction time jumped to days.

In standard interbank settling times, the transaction time takes days. But that's because transactions will automatically abort if they don't clear fast enough, and banks will take as much time as they can to actually close the transaction so as to avoid having to reverse it after the fact. In practice, many banks are happy to credit your balance with the deposit immediately (if the deposit is small enough, about $5k with my bank) without waiting for confirmation.

Of course, the time it takes to settle the transaction actually doesn't matter that much for the most part. In many cases, the transaction clearing time is going to be an insignificant portion of the time between invoicing the transaction and actually sending the goods.

[thedancollins]

And the reason for the spikes - blockchain technology struggles to handle large transaction volumes. The consensus mechanism monitors block creation time and tries to keep it at 10 minutes. Ideally, there are never more than a block's worth of transactions to be created at any given time. When that is not the case a backup occurs and yes, the settling takes far too long. This is the technical challenge that must be overcome before a PoW backed blockchain should be considered "viable" ready-for-prime-time. It is a significant engineering problem that I am excited to try to solve.