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> Any card can be converted back into digital bitcoins at any time, but doing so destroys the card.

What if you can convert it without destroying the card? How can anyone check "offline" whether or not the card still has the money?

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I don't think you can be certain offline, but it looks like the back of the card has an address where the money is stored. Presumably this will indicate if the card has been redeemed. It also lets you be sure someone didn't just print up some cards and hologram stickers themselves.

My guess is that, as someone accepting payment, you refuse if the card already has its hologram on the back peeled off.

I don't understand why an intact hologram is a proof of security. What if you saw through it?

And not just me, I mean lets just say I'm being ignorant and hologram is perfectly secure. How are you gonna convince the masses?

It's already an acceptable approach with other money substitutes (gift cards, pre-paid phone cards, etc), where you have to scrape off a film to get a code.

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