It is so simple to use right? During the Apple's conference, they keep saying the 3 main point : Fast, Secure and Private. 

But the real question remain: is it safe ? 

From what Apple described, it's safer to use Apple Pay than what we are doing currently. 

For the current situation of paying using Credit Card: we are giving our card to the cashier to swipe the card. It's very dangerous as the person can view your card number and the code number behind your card. 

As for Apple Pay, your card number and security code number are actually private. Apple and the merchant wouldn't know it. Furthermore Apple said that whatever the transaction you made, it is Private. They will not know anything about it. 

How they actually store your card information? Apple said that whatever card that store on the phone, are on the phone itself. It's not on the Apple server. Hence they would not have your credit card at all. All these are possible because of the chip inside the A8 processor, just like the Touch ID. When you scan/add a new card, it would assigned the card with a uqiue device account that is encrypted in the secured chip. When you purchased stuff and paying by scanning your phone/watch, the uqiue device number along with transaction-dynamic code are used to process your payment. Hence your card information are never shared, it will remained secured and private to you.