I feel that most merchant (especially off-line) reward programs are broken, so what if shopping at any store could give you sats back. A universal easily exchangeable "points system" that can be redeemed instantly and by the way.. goes up in value with time.
The full business model is note set yet, but here is the proof of concept, please avoid abusing it, so other people can try it. There are some free sats, although not unlimited ;)