Forgive my ignorance but what would be some practical use cases for this, for someone who hasn't been doing any GPU programming to understand? I guess Machine Learning?

currently, when you want to write a sahder, you have to use a specific language for that (gl/sl or some other). That's a pain because that language is C-like and most likely pretty close to your host language (C,Rust,Zig whatever). Moreover, you must pass information to these shaders (uniforms) and it means you have to write code to copy from you haost lang data structures to the data strctures of the shaders (which , once again, are pretty close to those in your host language). Shader languages don't usually have "import" mechanism, so building with them is painful. And their syntax is very light, so having syntactic sugar coming from the host language would be cool.

So yeah, writing shader in something else than Gl/SL, wgsl would make our life so much easier...