I don't know exactly how they work, but I would assume that, unlike what it says in the article, you shouldn't send BTC to the original address - or, rather, you shouldn't accept a satscard where that is the case, as the private key has been exposed. Unless the actual signing is done on the card, like a tapsigner. But if that's the case, why are they two different products? I don't know, I'm just "thinking aloud".