It already made sense to have a SPIRV- and SPIRVCross-based shader pipeline in cross-platform engines with WebGL support though (because you'd want to author shaders in one shading language only, and then translate them to various target languages, like some desktop GLSL version, then separate versions for GLES2/WebGL and GLES3/WebGL2, and finally HLSL and MSL, WGSL is just another output option in such an asset pipeline).