Not so much in the language itself (I'm not a fan), but the process of embedding Lua and pushing data into a Lua context and pulling data out of a Lua context is so simple the first time I got it working I thought, "Surely I'm missing something, it can't be this easy." The ease of integration with C or C++ makes it worth strongly considering when you need an embedded scripting language. But, as I alluded to, Lua as a language is pretty awful. Lua's tables are an abomination in my eyes.
A few years ago I started a simple RPG game engine that uses Lua[0] as its scripting language. I never got very far with it but considering I had zero clue how to even begin approaching the problem when I started I'm pretty happy with how far I got before I lost interest.