You embed the scripting language VM in to the game application and expose some API to it - which is then used to build the game content - things that require cu

You embed the scripting language VM in to the game application and expose some API to it - which is then used to build the game content - things that require customization but aren't performance critical or technical, like triggers/events, ie. what happens when character X enters area Y, when user presses X, where it would be ridiculous to recompile the code just to modify it and you want non programmers to be able to do the customization in a "safe" language - sort of like javascript/DOM allows designers to do some programming while the grunt work and low level details/performance critical parts to the C++/native implementation.