Waiting a day for a transfer now seems hilariously outdated now to me.
I understand there are other benefits to bitcoin but something seems inherently wrong if transfers have to be intentionally delayed so long to make the system more secure.
My understanding is that the inconvenience of ACH is by design - they are security delays. If you need to send money from one account to another instantly, you use a wire. If you have the amount of money in your account that is typical of people that need to send wires, they are often freely included with your higher-end checking account. Wires send the money instantly.
I commonly see wires hit within ~30 seconds of hitting the "confirm" button, and almost always within <=5 minutes, and that's between separate US banks.
Ikeboy(sibling comment)'s explanation is as good as you'll get, in my opinion. And you can even skip steps 2 and 3, as we have done for two years on BitMEX.
It's our opinion that customer funds are simply too important to expose to this kind of risk, so we process withdrawals only once a day from airgapped multisig wallets. It's a bear, and it's slow - we developed a few internal tools to make the review process easier and separate signal from noise - but aside from some manual work we've never had a problem.
The #1 surprise, to me, was that customers don't mind the inconvenience. Sure, a few wonder why they can't simply get their funds immediately. But it's explained to them, they seem to appreciate the sensibility of managing this risk seriously. Compared to alternatives like ACH, at least it only takes one day and runs on weekends.
I can't imagine a nightmare worse than losing millions of dollars of other people's money. I hope for Bitfinex's sake that they are able to recover a portion and continue operating. We've spoken personally with much of the team and enjoy the relationship. They - and their customers - don't deserve this loss.