The Vulkan version will really add a lot I think. I would guess most people are most interested in an OpenGL to Vulkan comparison. Similarly (possibly more interesting to people, I don't know?) the DirectX version.
Nice comparison.
Nice comparison.
In particular, resource binding is very different between Metal and Vulkan. Metal's resource binding is more simple/traditional. Vulkans is... sensible, but substantially more complex.
Caveat: haven't used either professionally, read the code in the repo, or had my morning coffee. I've also never touched Dx12, but I've heard it basically works the same as Vulkan here.
So, in practice, if they are noticeably different in the dynamic case, you'll see those differences in the "as if it were dynamic" case, which is most graphics demos of this sort.