[Jasper_]

> Real-life VMs don’t interpret, they JIT compile.

Pretty much every real-life JavaScript VM is tiered, and has an interpreter, which gathers data about expected usage which the JIT will use to inform its optimizations when it goes to generate machine code.

Still, you'd be surprised about the performance you can get out of a basic interpreter. Games have used Lua for years. I've written and reverse engineered plenty of custom bytecode for various reasons in the games space. It's a useful tool to have, and there are a lot of situations where performance either isn't the goal, or the large amount of tricks used by JITting VMs isn't helpful.

The dispatch loop you point to is just about using a C extension (computed gotos) to gain a few extra performance points. You can learn about it in about 30 minutes after knowing what a VM is.