BuyFromEU

We've had a standard for this since 2013. Scan code, your bank app opens with the transfer as a template, you authorise it. Now, with SEPA instant transfers, it's guaranteed to arrive within ten seconds. No pointless third parties involved.

I see this being useful for non-permanent shops, like a strawberry farmer with their seasonal stand, flea markets, etc, but for permanent shops POS systems are superior, whether chip+pin, rfid with card, or rfid with phone. It's also useful for private-to-private transfers, my bank app can display the code, someone else can scan it, choose an amount, done. In the wild I've only seen them on paper invoices, just another (additional) way to write "please send the due funds to ".