As a B&M merchant I'd love to use such a product. My only change would be to have square api integration if it exists. Square makes fiat payments easy since they sell hardware and it natively connects to inventory management which is very important.

Also if it were to run on nostr rails that would be excellent because as a communication layer, the messaging can adjust inventory in real time by connecting the POS with back end database. It could also serve as receipts and integrate nicely into a client side store loyalty app.