GUI support allows you to run desktop operating system apps on mobile. Docking the device to a keyboard and mouse and external display in the future would allow using your phone like a desktop PC. You get the benefit of running a desktop OS over a device with strong hardware security and a proper secure element unlike a desktop. Adding this GUI support is also a stage into working towards support for running Apps within GrapheneOS virtual machines for stronger sandboxing and isolation. Additional security.

Awesome!