Okay, so I just read the Bitcoin-fan objections to MintChip, and it seems it boils down to two points that they see as negatives: the currency is controlled by the Royal Canadian Mint, so they can make new digital coins, and if you can crack the secure chip then you can potentially double spend. However, these two points are what gives gives MintChip it's real world advantages: the currency is linked to a real currency and controlled by an authority that is overseen by the democratic institutions of the nation state, so it has value. Double spending is an unfortunate reality of allowing offline transactions, but in the real world being able to do offline transactions (like real cash) is very desirable.
Many encryption enthusiasts miss one important point when it comes to digital cash: security and convenience are a tradeoff, and the public will usually value convenience over security. With the right equipment, it is possible to copy and double-spend real cash. These are issues that society already has to deal with. The question is not whether it is possible to defraud digital cash - the question is whether it is worth a criminal's time to do so. A potential criminal is not going to use an electron tunnelling microscope to extract the cash from a micropayment card that is intended for payments of less than $10. Yes, it is theoretically possible, but in practice there are more profitable ways for criminals to make money.
Now, if there were an easy way to "empty" a payment card though some stupid exploit, then I can understand that being a problem, but that assumes that there is such an exploit. I would be willing to bet that a system that has been checked by the world's best cryptographers, using open protocols, would be more secure than physical cash notes. Not perfect, but more secure, and that is all we can really ask for. In the real world, it is trivially easy to steal the cash from someone's wallet. Digital cash doesn't need to be perfect, it just needs to be better than that.