If every self checkout was similar to others, but each of them want to make things different.
Different and worse. How do designers keep seeing other checkout system and think: "You know, I think I see a way that we could make this process slower and more complicated...."
I don’t understand why the card reader and the screen are separate units, just combine them like those Square kiosk things that counter order places have.
Security is a big reason to never combine payment processing and user (the store) defined ui.
Could you clarify? Because I’m pretty sure that’s not a thing.

stripe recommends it for card reader to smartphone at least, and it looks like home depot is an example of why it should be done between the card reader and the pos.

stripe.com/ie/…/how-do-card-readers-work

…pcisecuritystandards.org/…/accepting_mobile_paym…

How do card readers work? | Stripe

Card readers are a key part of a business’s payment system. This guide covers types of card readers, how card readers work and how to use them.

I get the phone thing, because phones are relatively insecure devices, but they could have functionally separate systems in one box.

The main problem I’m trying to solve is the weird UX where I need to select a payment method even after paying on the payment device. If it was designed as a complete set instead of separate units, I think they’d fix that.

Because at the scale these stores work at. It’s cheaper to have different units you can replace, repair and upgrade at different intervals as needed.