I’ve been reading about the Curve card.
From what I can work out, it’s a MasterCard prepay card that, instead of you topping it up with credit, provides a “token” when you use it for a transaction which links the transaction back to Curve. The transaction can then be re-charged to any of the cards (credit or debit) with which you’ve linked it.

A beta Curve card
It’s multi-currency, and will give you a decent exchange rate (MasterCard rate + 1%) without commission on foreign currency transactions.
One of their big claims is that you can use it to pay with your Amex card (and get loyalty points) anywhere that takes MasterCard – which is more places than take Amex at the moment.
They also suggest this is a way of reducing the number of cards you have to carry to one. Indeed Ted Truscott has written a review after using Curve for a week where he suggests this is now the only card he carries.
But I’m skeptical.
First, from what I can see from Curve’s FAQs by using Curve you compromise your consumer rights: if you use a credit card directly to buy something then the transaction is between you and the credit card company, and your final recourse in the event of a problem is to the credit card company as the vendor. The same protection doesn’t apply to debit cards – they’re essentially the same as paying with cash. And using Curve give you the same consumer protection as using a debit card:
“using Curve is not a direct purchase from the user’s original card, so the purchases are not covered by Section 75 of the Consumer Credit Act”
Second, I’m concerned that putting all your cards on Curve gives you a single point of failure: while your individual card details will be concealed, if the Curve card, the privacy of your app, or the token the card uses, becomes compromised surely all your cards are at risk?
Third, if I were to use a Curve card, and put all my debit and credit cards on it, I would reduce the number of those in my wallet from four to one. And I could carry my Euro debit card which I normally only have with me when I’m travelling. But I also have loyalty cards, membership cards and my driving license to carry: I couldn’t stop carrying my wallet – I’d merely have six cards in it instead of nine.
And fourth, I already have a MasterCard that gives me low-cost, commission free foreign exchange purchases.
So for me, the only real benefit would be that I could use my Amex card in a few more places. But I already have a MasterCard, so I can still buy stuff in those places – and get consumer protection on the purchase which I wouldn’t get if I used Curve (or the Amex alone, as it happens, since it’s a charge card).
So, while I’m tempted to try it – it’s new technology (and I’m a sucker for that), I’m not quite tempted enough to actually part with the joining fee yet.
I’ll be keeping an eye on its development…