Performance requirements determine if a system is actually used or not.
The Consumerium buying signal seems to have very tight timing requirements, and also must minimize visual distraction. If it is also handsfree i.e. via a headset, that is also very important, as it might save seconds of fumbling, and enable use in situations where even a one-handed interface is of no use at all.
Most breakthrough design happens by thinking hard about actual performance questions. Some to consider:
- how long can the user tolerate waiting to receive the Consumerium buying signal? if they must have it at the retail shelf immediately, this is going to be difficult for even in-store radio to satisfy; if they can wait until the checkout counter, or a visit to a retail kiosk, then a lot more possibile ways to deliver the signal exist;
- how long does it take to shift eye contact to a video display from what you are looking at, like the aisle or your children, and shift back?