Surely you mean WebCodecs rather than WebGL/WebGPU? AFAIK no encoding primitives are exposed by WebGL/WebGPU.

The advantage of shipping an encoder in WebAssembly for is that you don’t have to rely on the browser supporting the specific codec you want. e.g. Safari and Firefox don’t yet support WebCodecs at all, but do support WebAssembly.

Do you mean those features added to WebAudio or that you could use WebAudio to implement those features, because the latter is not really true