As well as sandboxing there’s the potential for better startup performance. Wasmtime have described how they can achieve microsecond startup times using virtual

As well as sandboxing there’s the potential for better startup performance. Wasmtime have described how they can achieve microsecond startup times using virtual memory tricks to reset and reuse a module isolated between requests. https://bytecodealliance.org/articles/wasmtime-10-performance https://bytecodealliance.org/articles/wasmtime-10-performanc... This is faster than forking a process because there are fewer operating system resources to manage. CGI starts a new process rather than forking an existing one which makes it unsuitable for use with languages such as Python or JS which have slow initialisation times (milliseconds.) Wizer is able to snapshot a WebAssembly module to avoid that work. So in combination with the fast startup that brings initialisation down to microseconds. Now runtimes are still somewhat slower on WebAssembly than native, and much slower for JITed languages since the JIT cannot run in WebAssembly. But there are many cases where startup time dominates and this will be faster overall for cases where you need per request isolation.