In an embedded context lua is definitely still useful without those things, although coroutines are nice to have almost all of the lua work I've done hasn't use

In an embedded context lua is definitely still useful without those things, although coroutines are nice to have almost all of the lua work I've done hasn't used any of those features. IO and pattern matching seem important if you're using lua for text processing, which isn't the only useful reason to use Lua.