It is new on the Shopify App store, hence the lack of reviews. It works with growave via API integration. You can install jericommerce and growave app tiles at the POS and when identifying the user via QR it links the associated balance to the user.
The QR could be printed, but the user and related digital pass and QR would have to be created anyway, and it would lose all the digital properties, as push notifications, campaigns and associated links.