Have you ever bought something only to regret it later as you run into a spending limit on the card you used? If you live in in the right country, you might have a way to overcome this particular strain of buyer's remorse. Curve is giving its British and European Mastercard users the ability to switch a purchase between credit or debit up to two weeks after the transaction took place. If you realize you're going to go into overdraft, or that you should have expensed dinner on your corporate credit card, you can make a change before it's too late.
The payment swap is free and should take less than 10 seconds through Curve's Android and iOS apps. About the only practical limit is a £1,000 purchase ceiling -- you'll still need to think carefully before splurging on that new TV. Even with that catch in mind, this is promising. Most smart payment cards focus on slimming down your wallet and little else. Curve, on the other hand, is taking advantage of technology to provide some genuine flexibility. It's not certain that other companies will follow suit, but there could be a day where you're rarely locked into your purchasing decisions.