These are not the mini smart cards, but credit card sized cards. See users guided here. I have never used one of these either, so that is all I know about it.
Smart cards are portable credit-card shaped devices with internal integrated circuits. The top surface of the smart card usually contains an embedded processor located under the gold contact pad. The combination of the small size and integrated circuits make smart cards valuable tools for security, data storage, and special programs. Using smart cards can improve system security by combining something a user has (the smart card) with something only the user should know (a PIN) to provide more secure user-authentication than passwords alone.
They aren't something you use for any storage or program like media cards, SD or CF cards etc. or USB flash drives. Institutions issue them.