ReactOS helped me in a pinch recently when I needed to run a Windows only app to configure an IoT device. As I don't own any Windows system, it's very nice to have an option other than buying or borrowing a copy of Windows.
For stuff like simply configuring a device, any old ISO or even VM image available directly from MS should do.
edit: typo
I hear this allegation a lot without anyone being able to explain how an offline installation would even be able to do this...