The video just hit he nail on the head. So I deduced my own layman definition of Immediacy & hyper-immediacy, for designers:

All interaction is though a medium. We seek the interactions to be immediate, for achieving this we try to reduce the need for a medium. The lesser the dependence on a medium – the more “immediate” is the interaction . Eventually the goal is to achieve hyper-immediate (no medium required) interaction.
What Zong is trying to do here is two fold:

• Reduce the number of steps involved ( one always remembers the phone number; a credit-card has to be found in the wallet at the other end of the room.)
• You no longer have to travel the psychological distance of giving out the credit card to the infinite web. ( I know, I know. There are issues with giving out the phone number too – but I hope you get the point of : medium, distance & immediacy.)

If you want an even simpler definition – My designer friend in Dubai always said “I design for my lazy self.”