Comment by ndiddy

One example: I use software called Looking Glass on my PC for interacting with a Windows virtual machine. I have two GPUs in my computer, an AMD one for the Linux host and an NVidia one that gets passed through to the Windows guest. Looking Glass then captures the NVidia GPU's output and displays it in a window on my desktop. This allows me to use Windows software in the VM and get acceptable performance (Windows has basically required graphics acceleration to run acceptably after 7). The problem is that the NVidia GPU will not do anything without having a display connected. NVidia Quadro GPUs support dumping a monitor's EDID and then mapping that file to an output (so the GPU always thinks that monitor is connected to that output), but their consumer-grade GPUs don't support this. That's where the dummy plug comes in.