You can't re-hide the private key because once you've imported it into something, you've invalidated the guarantee that there's value on the card, and it no longer serves any purpose.
Sure, there might be no money in that address any longer if I move the money out. However if I don't have any money in there then I don't get to carry around my groovy card as a way to remember my btc address. I get it, these things are more like paper wallets to be kept away safe. It's just that they look cool so I'd be wanting to show one off.