Some engines do use C++ scripts. The question is what do you want them for? Who makes them? Who calls them and how? How do they execute. If you mean to have them as something someone in an editor can piece together or call from a trigger, they may make sense. But if you are the one doing all the game logic then I don't see the need for them. Personally I would rather give a higher level tool to nonprogrammers if they want to do something simple like a trigger, and for game logic make things more 'data driven' ie you don't just fire one-off scripts from triggers at whim.