No problem to copy the cards. You might want to enlarge them to read those tiny phone numbers on the back (OK, I've got over 40 eyes).
I've got copies of the cards, plus bank and 401(k) account numbers, driver's license, social security card, passport, etc, but they're not in a safe. If I have to get out of the house in a hurry, I can't take the safe with me and I may not be able to get to it. I've got everything in a backpack by my bed so I can just grab it and go. It includes a car key, a disc with docs from my computer, some cash, and copies of my marriage license and divorce decree (in case I want to marry the fireman who saves me). It even has a clean t-shirt and underwear (the t-shirt was from a walk I did to raise money for the homeless
).
Yes, I know, there may be a fire downstairs (due to one of my cooking efforts) and I may not be able to get the backpack which is upstairs. I also gave copies of everything to my sister. She lives in another state and put it in her safe deposit box. So I'm ready for ... whatever.