Filesize doesn’t matter, if the functionality is missing.

Lua is meant to be embedded into other applications, not meant to be used on its own.

Wrong. Lua is meant to be used on its own, because it's so freaking good. It provides everything one needs to begin, while allowing for a wide array of libraries to be made. But I know you haven't made any serious number of scripts in either language, simply because you claim 'filesize doesn't matter', while Lua is so fast partly because of its size.

This is a design choice, because Lua isn’t meant to be used by its own.

Wrong again. Lua is amazing on its own, but third-party libraries make it even better.