Why does my Lumia 640 LTE beeps anytime I place a Visa payWare Credit card on it's NFC?

The beep is the usual 6–10 seconds NFC sound just like when connecting to another NFC capable phone.

The beep happens when I place the Card behind the phone where the NFC reader is located.

Here is a picture of one of the card. Note the Wifi Logo..

Image may be NSFW.
Clik here to view.