The card is generically called a Smart Card. That little gold thingy makes this card a "contact" smart card.

Contact smart cards have a contact area, comprising several gold-plated contact pads, that is about 1cm square. When inserted into a reader, the chip makes contact with electrical connectors that can read information from the chip and write information back.

These cards have the ability to store a lot of data! While mag-stripe cards usually only have a very long, unique number, which is read and compared to a database to find your account info, which gets displayed on the slot machine, these cards have the ability to hold all of that info!

Jim