A built in UPS is really helpful for moving from room to room around a home or office.

For a long time I've wanted something with all the properties of a desktop PC, but the ability to move it to another room while booted and without having to do multiple journeys.

A serious enough setup I could use it for work every day, yet still with the ability to take it to the living room to do stuff while supervising the kids...

Put the whole thing on a platform with casters and bolt the case and a UPS to the thing. With a solid metal base, you could put on a shelf for mouse and keyboard and a stand for a monitor.

This seems like a pretty achievable project if you have access to a workshop.

You can buy such a thing off the shelf. They're called "Workstations on Wheels" or "WoWs" and they're everywhere in medical facilities.

For a device that may be deployed in or from a vehicle or locations which may or may not have 100% stable power, a built in UPS is great.

Also, that 'ups' allows one to move the device around - it is called out as a mobile SOC.