You shouldn't be downvoted, your question is reasonable even if it demonstrates a misunderstanding. So it's not a wrapper over WebGL, it's a more modern, lower-level GPU programming model. There are equivalent efforts in native environments to replace OpenGL - notably Vulkan and (Apple's) Metal.

As far as I understand, the approach allows far more flexibility, at the expense of higher complexity. It's less "stateful" than WebGL, which basically gives you a big class that manages everything OOP-style.

It's the other way around. WebGPU is to Vulkan what WebGL is to OpenGL. It's less low level than vulkan though.

WebGPU is to WebGL as Vulkan is to OpenGL, a lower level, low overhead graphics API.