Welcome to the 20th Century. Oops, we're not there any more!
I deliberately wasted several hours of my bank manager's time once. When he sussed what I was doing, he asked why. Because it had taken four days for a cheque to clear - a cheque I had received every month from the exact same employer, for many years, and paid in immediately using their fast-track cheque machines that take a photo of the cheque for you, then wrap it in an envelope and send it on.
And because of the delay, for a fraction of a second, my bank account went overdrawn by a few pounds even though the cheque was in the bank's possession. They delayed and delayed it, further than necessary or normal, in order to ENSURE I was charged for going overdrawn. The cheque was an amount enough to clear the transaction they bounced several hundred times over. They then charged me £50 on top as an administration fee.
I'm an IT guy. I know that transaction takes milliseconds to process. The fraud selection? That's in place 24 hours a day on CC transactions anyway - there's nothing special about that. This is just an extension.
The antiquated system of "it has to arrive at the other branch for the cheque to clear"? Nonsense and zero justification when you have the cheque in your possession. This stuff is chicken feed on the bottom of the banking balance sheets, but they can play it and make money by making it slow and cumbersome. Because most people will just keep quiet and pay it.
The only question I really wanted an answer to? Has four hours of your time cost the bank more or less than the (unfair, I would posit) overdraft fee you charged? What about the loss of my banking business? How much has that cost you?
Happened to run into the same guy at another branch when I was going in with my ex-wife to sort out her account. He ran a mile.
Sorry, guys, you can make all the excuses you want, but that transaction system is slow BECAUSE YOU MAKE IT SO, not because it needs to do. The real-time clearing is already in place - try using a blocked credit card and see how long the gap is between you reporting it missing and all your vendors saying they couldn't charge you card for your usual monthly payments. The same applies to Direct Debits (in the UK) and myriad other banking technologies.
I once recorded a 3 minute interval between my phoning my bank to cancel a Direct Debit and the company that it was paying phoning me up to threaten a lawsuit over non-payment (long story short, they "agreed to overlook the matter", including the complete refund they'd had forcibly taken from their bank account, after I offered to initiate the lawsuit for them).
It's all nonsense. Banking systems do nothing special nowadays, especially not the personal / small business banking sector of the industry. They don't need tons of supercomputers and overnight batch processing - they just do that to eke out to the last second how long your money is with them.