With this card you fund are held as BTC. As far as im aware anyway.
That's something that the details are still being worked out on it seems. Most likely no, there will be a USD debit balance for the card. But BitInstant will make it easy to convert bitcoins into USDs (1.5% fee) and either no confirmation or 1 confirmation, which hasn't been determined yet either.
The problem I've seen up until this point from elsewhere is that this transfer can be done, but not in real time. But perhaps this specific issuer is able to offer real-time transfer, and then it is just moving the USD credit from BitInstant's account with the issuer to the cardholder's account. It sounds like it would be so simple to do this but for some reason it just isn't offered that way (real-time) anywhere, as far as I know.
The other part that was left unanswered was if a card swipe (authorization) is attempted for more than the USD balance, could the authorization trigger the conversion of a sufficient amount of Bitcoins so that the authorization would have sufficient funds and be approved. That would allow you to never have to manually transfer from your bitcoin account with BitInstant to your USD account. I'm thinking this is like way down the road, at best, but if they can do that, you never need to carry a USD balance, the bitcoins are converted with each purchase.
We know there is demand for this. Anyone who has a reloadable debit card that accepts Direct Debit (ACH) is able to convert their bitcoins and withdraw to their debit card now -- it just takes a day or three for the funds to get added. This can be done from BitFloor, Camp BX, FastCash4Bitcoins, and others -- today.
And there is also a growing number of people cashing out to PayPal, which, can have tied to the account a debit card. Those account-to-account (A2A) transfers are spendable immediately. Or you can convert Bitcoins to MoneyPak and load your card that way -- another method that is essentially instant. So this movement from bitcoin into debit cards is already happening, just that what BitInstant is saying makes it the easiest, fastest (and in most instances, cheapest) method for this.