I know there are many programming gurus who say no-no to invoking system calls because of overheads and what not. But the way I see it, if I am to run a relatively sophisticated model (say, statistical), the packages of which are available in a scripting language like R or python, don't the benefits of invoking a system call to a run a script in terms of reduced hassle and programmer time outweigh the costs of implementing the model on C++ if there aren't any off the shelf libraries in the former out there.
So how is it faster?
You Should actually NEVER use system.
You can create your own "scripting system". But system isn't good at all. http://www.cplusplus.com/articles/j3wTURfi/