The virtualization that WASM does is actually cleaner than what other similar attempts do. In a field where implementations typically end up being a thin veneer over JS objects (which means you typically end up having to get your hands dirty and work with JS bits here and there), WASM should clear the slate clean enough for most uses, so if you write Python and target WASM, you'll not have to write a single line in JS (well, maybe a standard cookie-cutter loader while the thing downloads the first time, but that's it).