This is the best summary I could come up with:

The NVK open-source NVIDIA Vulkan driver has finally been merged into mainline Mesa for easing development of this driver moving forward.

This complements the long-standing NVC0 Nouveau Gallium3D driver that has provided open-source OpenGL support.

This NVK driver though is contingent on new Nouveau user-space APIs that have yet to be mainlined.

Until all the NVIDIA GSP bits are squared away in the Nouveau DRM kernel driver upstream, the performance with recent generations of NVIDIA GPUs is also to be very slow -- an unfortunate state we've seen since the GeForce GTX 900 series due to signed firmware restrictions around power management / re-clocking.

At least getting NVK upstreamed into Mesa now will help in easing development of this driver moving forward and making it easier for enthusiasts to experiment with this open-source NVIDIA Vulkan driver once the kernel bits are merged.

He confirms the changes to the Nouveau kernel user-space API will be sent in for Linux 6.6.

I'm a bot and I'm open source!

Such a huge step to finally ridding ourselves of that garbage proprietary driver stack. There’s still so much work to do but hats off to the team!

In the end, is there any use case for Nouveau? Assuming you're running a GUI?

Or is it for all those people that are just running a text interface on top of their GPU?