WebAssembly Is Boring Now, and That Is the Point

Where it genuinely wins

Image and video processing, cryptography, parsing large files, anything CPU-bound that used to require a round trip to a server. Doing that work locally is faster and quieter than uploading a file to find out.

Where it does not

DOM-heavy interface work. Crossing the boundary between WebAssembly and JavaScript has a cost, and a UI is mostly small operations against the DOM. Rewriting a slow interface in another language rarely fixes it.

The download is part of the runtime

A multi-megabyte module can undo the performance it was added to deliver. Measure the whole experience, fetch, compile, execute, not the execution you were hoping to brag about.

Choose it for capability, not speed

The strongest reason is reusing a library that only exists in another language. A mature codec or solver you do not have to reimplement is worth more than a benchmark.