When should you use WebAssembly (WASM) and what is the integration pattern with React?

Imagine you built a super-fast toy car using metal and special tools (like Rust or C++). Then you pack it into a special box (the .wasm file). JavaScript opens the box, checks it is safe, and hands it to your React app. Now your toy car runs inside the website at metal speed — great for heavy math like blurring photos or cracking codes, but not useful for moving buttons around (JavaScript is better at that).