Well in this case, it's more integrating Python with C i.e. writing a C callable and calling it from Python.
I'm not really a Lua fan personally (the confusing indice and ordinal notation scares me), but I can see why it makes sense for integration purposes. Clean, simple, to the point.
Having just completed a large project with Lua, I have to say that the indice/ordinal notation thing is something that we quickly got used to. In fact, some nice succinct idioms work because elements run from 1 to arraySize (inclusive).
I'm not really a Lua fan personally (the confusing indice and ordinal notation scares me), but I can see why it makes sense for integration purposes. Clean, simple, to the point.