Their little example video shows what a striking difference it makes:

One of the major changes here is how they handle shader building with Vulkan, which uses all CPU threads to do it in parallel so it works your machine harder but the result is a much smoother first-time gameplay experience while it builds up a cache to load from. Right now they're still keeping OpenGL as the default API but they're suggesting people test with Vulkan now too, as it should have a significant boost in performance and compatibility and that 'rendering and shader build performance almost always beat OpenGL'. The result? They say it fixes 'an innumerable amount of rendering bugs, reducing shader build times, improving compatibility, and increasing performance by over 30% for all GPU vendors' and is one of the biggest changes made to date.

In their fresh update blog post the team notes how it took them six months of work to accomplish with around 50,000 lines of code written but it's finally released.

While it's still a real PITA to setup, the Nintendo Switch emulator Yuzu has released what they call Project Hades, a massive rewrite to their shader decompiler which is a big thing for it.

Yuzu emulator requirements