WASM has its moments, as you can see in this[1] benchmark it outperforms JS and native addons on certain tasks.
Since the bottleneck with native addons is usually data copying/marshalling, and we have direct access to WebAssembly memory from the JavaScript side, using WebAssembly on this "shared" memory might become the best approach for computationally heavy tasks. I wrote about it a bit here[2].
[1] https://github.com/zandaqo/iswasmfast
[2] https://medium.com/swlh/structurae-1-0-graphs-strings-and-we...