I'm a happy wasm user, last week I was looking at adding support for psd file on my app [1], the choices was in between using a full js lib that is almost 1MB large, doesn't work very well and is slow OR leverage some C stuff. Without any kind of optimisation, the wasm version is 10 times faster and 5 times smaller and that's before digging through SIMD. There will always people complaining about a lot of things but wasm is already fine enough for a lot of use cases

[1] https://github.com/mickael-kerjean/filestash