lua is awesome reason #42069: i have a document language i designed as a medium-weight replacement for markdown that's well-defined and easier to parse. i was able to write a parser+converter for it in lua and turn that into a completely self-contained binary by compiling it to bytecode and wrapping it with a C shim. if you tried to do something like that with Ruby (or hell, even Go!) you'd have a binary megabytes long, at the very least -- assuming it was even possible. my wrapped formatter was only a few hundred kilobytes, and that was the one that statically linked lua.

and ofc i could have made the statically linked one even smaller by manually compiling a version of lua without the interpreter, just the VM