WASM is not native code, so there's no guarantee it will have the same performance. There have been earlier attempts to have cross-browser and cross-platform na

WASM is not native code, so there's no guarantee it will have the same performance. There have been earlier attempts to have cross-browser and cross-platform native code execution on the web, not to mention plenty of nonportable web plugins, but WASM's just-in-time compilation of a low-level bytecode is a good balance between performance across different architectures and feasibility of sandboxing code execution (you don't want a web app to gain access to your filesystem and kernel syscalls with impunity)