[xKingfisher]

My dream for something like this is having everything on one card would let you manage the complexity a lot better.

Having one single interface to pay all bills and see spending breakdowns aggregated across all your cards, recommending the optimal order to pay down cards (if you are going to carry a balance).

Then on top of this, automatic fallback in case one card is declined, new numbers for every online transaction (not tied to a single provider).

You could even layer on top a simple scripting language to choose the card to be used for a given transaction. E.g. Use my rewards card when buying gas, but if I've maxed out the points then use the lowest interest card. Or round robin the cards to spread out the balance.

Or imagine a group outing where everyone can all combine into a single virtual card, with the ability to distribute charges however you want on the back end.

There are a ton of cool possibilities available (albeit very challenging to get right). And in theory, many people have at least 2 cards for redundancy purposes. Add in no fee rewards cards (Target, etc) and it will add up even for non hardcore points collectors.

[linsomniac]

One of the Plastc alternatives, I can't seem to find it now, was a device like Plastc, but also a yearly subscription fee, because they promoted the benefits being that the card would automatically switch between your available cards to optimize rewards.

At a gas station you would use the card that had the best gas points. At the grocery store it would switch to the card with the best grocery points...

I was never interested in it, because I don't really want to manage many cards, but I can see the appeal in it.

[huebnerob]

This sounds like a genuinely useful technology that will sadly never make it past the Big Credit gods. Card providers seem to make their profits when you're not managing your card usage so intelligently.

[gkanai]

Moneytree does this in Japan. You register all your accounts with it and you can see them all and manage them all in one interface.

[dboreham]

Or you could have zero cards given that everyone trots around with a supercomputer in their pants these days..