If this is a cute way of publishing your public address as a way to receive BTC then it is cute, maybe even classy.

If it is supposed to be a way to send money, then it is useless (or at least insecure). If the private key is printed on it (as a set of numbers or QR code or whatever) then all I have to do to steal the BTC is look at it, maybe even from a distance. I can use a camera with a telephoto lens and take a picture of you holding your card. As soon as I do this I can spend your BTC.

If you give me one of these as payments for something, I have to run the transaction then and there to make sure the BTC hasn't already been spent. It is not a way to perform a BTC transaction offline. It is not a way to securely hold BTC.

I suppose you can take the private card and keep it out of sight (literally), but why put it on a wallet size card if you aren't going to carry it around?