I feel like the primary reason this is pointed out that way in the article is to defend their stance on removing the older DirectX backend. For a very long time, DirectX (9 and 12) was the fastest backend on Windows, and I believe it still outperforms OpenGL.
For what it's worth, I have the Android build of Dolphin on my phone (Pixel XL) and it seems to perform more quickly under Vulkan, but has some major graphical problems that prevent it from being playable. I suspect that once those are worked out, Vulkan will outperform OpenGL, but I'm not familiar enough with the project to say anything for certain.
For what it's worth, I have the Android build of Dolphin on my phone (Pixel XL) and it seems to perform more quickly under Vulkan, but has some major graphical problems that prevent it from being playable. I suspect that once those are worked out, Vulkan will outperform OpenGL, but I'm not familiar enough with the project to say anything for certain.