Re: This update could take a while
Well, my normal reason for things like this using Windows is that products like System Center make it relatively easy to manage a fleet of machines, whether that fleet is a few hundred or a few million.
That's not to say that given a similar management system, that I don't think it would be more logical to stick a SBC (be it a PI, Jetson or whatever) in the back of a large screen and deploy that. In fact, I believe NEC do a nice looking range of screens that you can plug a PI Zero into.
That said, the fact they clearly haven't attempted to control Windows Updates makes me wonder if they haven't just bunged a spare machjine in there that isn't being managed.