This will be very useful for platforms (mostly game consoles) where JIT are prohibited / security risk.

At work, I use Lua 5.3 embedded into a large-ish (a few hundred thousand LOC) cross-platform (runs on Windows, Mac, Linux, iOS, Android) C application as a way to extend it. We have bindings for a lot of the C functions and use Lua for prototyping. We keep the code in Lua in production if possible, or rewrite in C if performance issues force us to.

Personally, I use Lua for a lot of other things including Web development.