by opening your mind to different ways of approaching problems.
Many of the scripting languages interact very well with the 'standard' languages like C / C++ and with Win32 / MS stuff (at least, Python has pretty good COM and Win32 support). So another reason is some languages let you do stuff with the 'standard' languages that would very time consuming to do otherwise.
So far I'm enjoying using Python; it can do some really neat things compared to C++. I think it's a more productive language than C++, but the big reason I'm using it (with VB and C++ COM components) is that I can take advantage of its scripting to build in easy customization. C++ is not a good solution for this.
Tony