fp64 is exposed in GLSL at least, but on desktop GPUs it's typically 16x (AMD) or 32x (Nvidia) slower than fp32. Add that fact that mobile GPUs and some Intel

fp64 is exposed in GLSL at least, but on desktop GPUs it's typically 16x (AMD) or 32x (Nvidia) slower than fp32. Add that fact that mobile GPUs and some Intel GPUs don't support it in hardware at all, it makes a lot of sense to leave fp64 out of WebGPU.