I think the biggest company using wasm in production is figma (though there might be others). Otherwise, here is an example where wasm shines. Say you have an editor (rvim) and you want to support plugins. Usually, you’ll have a language interpreter and ask developers to develop in this language. With wasm, you can give them the freedom to use whatever stack they want. Then you expose an interface for their wasm artifacts. This abstract the host OS away. Another example is game mods/plugins.