I'm not going to disagree with your generalisation there. However with Halifax, specifically, you input your debit card details as authentication when resetting

I'm not going to disagree with your generalisation there. However with Halifax, specifically, you input your debit card details as authentication when resetting your password / sending user name reminders. And since user names are non-memorable (the one assigned to me was a 9 digit integer!), you can find yourself using the user name reminder feature on Halifax more regularly than you'd normally expect.