||I am asking because I have an existential C++ crisis.
I know a subset of C++ that generally allows me to use it for CLI (command line interface) programs, which is not that much, considering the wide range of applications for which C++ can be used. The GUI C++ experience I've had was a couple of random MFC program I wrote and a class on using MFC. I don't know Windows API, which is probably what I am missing, since somewhere I feel that I "should" or "want to" write applications for Windows in C++. Looking further however, I don't think I want to write applications for Windows, unless perhaps I find a job with an already established company that does that.
I use PHP, Perl and Java for my current job, and not C++. I feel like I "should" or "would like to" use C++, since I've had a lot of training on it, but I don't as it is not the right tool for the job. Still I feel that I have this algorithmic C++ knowledge that mainly shines through algorithm contests. I feel that I could also be using it elsewhere, for something productive, like income-production. And I don't. Hence I put my soul-searching post here asking people what they are actually using C++ for, hoping that someone may say something I haven't thought of before, or at least to satisfy my world-view that people generally don't use C++ for things other than algorithm contests and school projects.
The list you gave is indeed impressive. My direction of work has been web development, which is probably not very conducive to C++ by its nature. But I still use C++ for contests, which are fun ... in a masochistic sort of way.