I'm sure the team behind Lightroom are aware of Vulkan API and it's wide support.
I understand that Lightroom currently uses OpenGL, if they can get better performance out of Vulkan, then that's a win for the company and for consumers.
I'm sure the competition will eventually add support for it.
Which for backwards compatibility, if Vulkan support isn't detected in the drivers, then LR could revert back to OpenGL, which would then benefit Apple users as that OS doesn't support Vulkan and instead supports their own api Metal.
Just a thought