Ultimately it appears to be software with more fans than productive users.
The focus of arcan is to make the final display target super flexible.
So X was designed to be network agnostic, the programmer could use the same protocol and depending on how the end user had it configured it could be displaying on the same machine as the program via local shared objects or on a remote machine via tcp. But X never was able to dynamically transition between the two, there was no way for X to move a window from one machine to another. This is a core goal of the arcan project. I think the thing that gets people confused is along the way there is also a lot of adjacent experimentation in really wild window managers and control scripts. That is, what crazy things can you do once you have this amazing window location flexibility.