What sys admin? They don't have any. The kiosks are entirely blackboxes managed from the US central. It works if it has a working network. The store manager can manage it from their iPad lying down on a beach. The card terminals send data
directly to a bank and it doesn't matter whether the box burns down while it crashes, the payment is recorded.
I built similar kind of self service box (self checkout) for a local store chain. I know the problem well. Main problems are costs, system administration and management. Our solution is just a simple Chrome kiosk mode browser window too. It's a smart solution.
We run it on AWS because no reason not to - simply pushing the SPA to S3 behind Cloudfront beats any other kind of deployment/hosting method. Some backend stuff runs in Lambda, some runs in ECS containers. All data in a managed RDS DB. Easy to use, easy to maintain, easy to upgrade, easy to deploy, easy to scale from 0 to several thousands kiosks...
I used to be a Windows admin (though admittedly the last Windows I managed was 2003 R2). Just the word IIS makes my neck hair stand up.
Especially if it should be holding payment data... Huh, damn. Wow.
You'd need sync to a global service anyways - it's a multi store chain. Your suggestion just makes everything harder and more convoluted - and it's just wrong, the payment terminal has its own network connection and doesn't need the kiosk to work at all. The kiosk just initiates the payment but the rest of it is handled out of it - and the kiosk waits for central service to confirm the payment. It's bullshit to connect the kiosk to the bank, we support many banks and keep adding support for more, and what if it's stolen, should we always be ready to rotate the certs on 1000s devices - the bank doesn't have appropriate api, so it's either that or again, a central service? Nah, we just turn it off in our admin panel.
I also used to be a Linux sys admin way before clouds. I built one of the first cloud services in my country to solve the problems of that. The company ultimately was out competed - but not by traditional hosting. By the big public clouds. Apparently the problems are real.
BTW coincidentally I'm just about to launch a new cloud platform. Nothing fancy really, but it's built on dedicated servers for performance. Last 3 weeks I spent working on stuff I could've done with 100 lines of Terraform/Pulumi with AWS. Maybe a proper sys admin like you could teach me? I am not happy with it at all, it's a major headache and I'm considering a hybrid setup because I just don't want to lose sleep over customer data and site availability.