I really like being able to easily statically link libraries into the lua interpreter. Spawn a process using libuv and wrap it in a native coroutine to get concurrent execution with fewer failure modes than normal. Embed sqlite and get a friendly repl over your database. Find some utility written in lua and it's similarly easy to embed.

I replaced python with it for misc code generator and admin tasks for that reason. Instead of whatever pip is called these days and global installation conflict nonsense, I can clone a single .c from github that contains lua and all the libraries I've found useful so far.

Mostly it just gets out of your way. Compiler feedback isn't wonderful when you get something wrong but it's adequate. Some conventions are a bit weird but it's fine. Lexical closures, garbage collection and native coroutines make up for them.