Sending from CryoBit Cold Storage
Yes, you would simply import the private key to your client or online wallet.

I think the purpose is to move funds to the address on the card, then keep the card in a place somewhere safe and not use it. For everyday use, I think high grade steel, ceramic cast engraving, fireproofing, etc. is overkill.

You can always send more money to the address after you have swept the balance, but like you said, using it once may compromise the private key.

However, I don't see why you can't use the card to send to an address in your Multibit wallet (or other client). This means only your own computer "saw" the private key. As long as you feel comfortable with that, I see no reason why you can't reuse the card. But, and I am not sure about the following, I think private keys change with every transaction, which might be why you have to sweep the address, rather than just take a portion, and also why you cannot reuse it.

I will post more once I learn more on this topic. Also, another user may clarify in the meantime.