You may want to read this summary of the arguments pro and con SPIR-V, made by Kvark a gfx engineer at Mozilla, so you have a more balanced view of the topic :

The summary exists in two variants: a graphic summary[1] and a textual one[2].

[1] https://kvark.github.io/webgpu-debate/SPIR-V.component.html

[2] https://kvark.github.io/webgpu-debate/SPIR-V.html