This is a super interesting project, and the video is really well presented and explained, if you prefer that format.
I think this method could be brought even further by using 'thin clients' (a cheap laptop or used office mini-PC), making it possible to access the main gaming rig from any room in the house as long as you have access to a good network speed.
Utilizing a 'dummy' HDMI or Displayport stick, which simulates a monitor for the GPU, you could then remote into the gaming rig from a thin client-like PC through Moonlight/Sunlight, allowing you to use it as a fully fledged gaming or workstation PC.
If anyone decides to go that route, be aware that AMD GPU's have pretty notoriously bad encoders, so I'd recommend sticking with Nvidia (Pascal/1000 series or newer) or Intel GPU's/Integrated Graphics (6th generation 6000 series or newer) for the Host machine. It's a little less important for the client, I think.
EDIT: AMD did actually improve their encoders in recent years, starting with the Raven Ridge integrated graphics APUs, and the first generation Navi cards (RX 5700 onward, the lower end cards don't have it).