One of the benefits of moving the different graphics hardware drivers over to using kernel mode-setting, an in-kernel GPU memory manager (whether it be GEM or TTM), and other newer X innovations is the possibility of now running the X Server without root privileges. By doing so, this of course improves the security since this very large chunk of code is no longer running with all of these high-privileged rights.Due to now living in a KMS-enabled world, at least on the Intel and ATI side (the NVIDIA side is still slowly but surely coming via Nouveau), it's rather easy to get the X Server running without any special rights...