The point is it would be better than Linux in whatever way that was the reason you were writing it, but you don't have to write hundreds of different device drivers to make your cool new kernel usable.
Shouldn't we start building hardware that have a builtin translation layer that makes them driveable by virtio drivers themselves? At least for the most capabilities?
I might be misremembering but I recall that Nvidia's BlueField DPUs use virtio when communicating with the host machine. From what I gather searching around it's virtio-net in specific
If it's written in rust, you might expect less security vulnerabilities (especially if the codebase is also smaller: NB this is potentially counterbalanced by the many eyes on linux). Maybe there would be some extra features you find useful.