The information posted is public, I except nearly every person patronizing anything will have a cell phone. While they might not be able to purchase with steem they will be able to see a menu, you can put any online payment method along side steem. The software doesn't need to only be POS, even just games while you wait for food paid for with cash is a network patron. Therefore, everybody who uses software distributed like this gets to interact with steem, making the platform more desirable.