Is that an honest time comparison? It looks like Wasmjit implemented a parser and jit compiler from scratch. Also, their emscripten implementation is much more fleshed out and it works in kernel space. Wasmer doesn't handle signals or multiple processes in Nginx, while Wasmjit does.
Because of that, we prefer to leverage on existing open-source projects (for example, for parsing or for the IR) that are already working, than to create everything from scratch.
