But webassemblies are just binary blobs or black boxes, so to speak. That code is able to do literally anything to your devices.
That's not how it works. WebAssembly is a binary instruction format, but it doesn't mean you have actual binaries which are executed by the underlying system. It will be used in browser's sandboxed environment, just like JavaScript.
WebAssembly describes a memory-safe, sandboxed execution environment that may even be implemented inside existing JavaScript virtual machines. When embedded in the web, WebAssembly will enforce the same-origin and permissions security policies of the browser.
That's not how it works. WebAssembly is a binary instruction format, but it doesn't mean you have actual binaries which are executed by the underlying system. It will be used in browser's sandboxed environment, just like JavaScript.
👉 webassembly.org