I would love to see this in the real-world.
Some of my clients are often small independent retailers, whose main focus is their online shop. However, every now and then they will attend and event, where they will setup a small stall. Having a low-cost to entry and temporary card payment method like these would be fantastic for them.
However, my only issue is that none of these seem to support chip and pin technology used here in the UK and a lot of other areas around the world. Seems that these payment providers are a little too US-centric to be of use in the UK….. yet!