I've read here and in other places that learning C++, C or other low level languages are a must to get a more low level perspective on development. I agree with this, but I find it hard to find a reason to use C++ over C# or similar languages.

Most of the work I do is web based, so there's no need for C++ there. Other work is windows based, and most things work fine in C# there, so what sort of situation could I use C++?

I don't do any high performance stuff, nor do I create games, mostly business applications. I'm looking for an excuse to expand on my C++ knowledge but I need some motivation other than 'because the internet said I should'.