The "unprivileged package management" is the important feature here from the GNU point of view. One of the philosophical underpinnings of the GNU project is empowering non-superusers as far as possible - that's why they've stuck with the microkernel design, too. The idea there is that non-superusers would be able to easily run their own filesystem or TCP stack, for example, since it's just a matter of running their own daemon.

Once you understand this, a lot of GNU's technical decisions make more sense.