Numpy is fast thanks to having much of its code compiled as a native library. They were purposefully working to reduce abstraction, since performance mattered

Numpy is fast thanks to having much of its code compiled as a native library. They were purposefully working to reduce abstraction, since performance mattered from day one. WASM is a huge step backwards in that regard. If you care about performance, just install Python on your box and "pip install numpy". Do you absolutely have to have it come in a browser now?