Something like that is more likely to work if it's the same exact hardware, an XP image applied onto a totally different system is likely going to BSOD when all the current drivers it has installed suddenly stop working. And XP being XP, you're not going to find new drivers for new hardware.

A lot of these XP machines running other hardware also have their own specific drivers and long unsupported proprietary middleware installed that won't transfer onto new systems easily.

But I do agree with you on the disk image, if only the hard drive on that XP system dies then that's an easy fix. Worst case OP would have to hunt around for an IDE drive if that desktop is particularly ancient.

Sure, I have an image and 2 or 3 identical HDDs to restore them to. I have my doubts the image would mount as a VM, but I can install a fresh XP in a VM and then try to restore the drivers. I'd only have to find a way to access a serial port - I know they exist as USB adapters, but can't be sure the software would recognize it accordingly. Would have to recognize it as a serial in the host OS and then pass through to the image. Which in theory should work, but in practice I'll only touch it when it becomes a necessity. And luckily there's a million old computers for cheap on ebay, so I hope I can just wait it out until the microscope eventually retires. It's been long since written off, and I believe there were plans to replace it within the next 5 years, max.