What kind of applications can be built using c++?
Of course you can write anything in any language. But there're areas where you can use only c++. Something that need to work as fast as possible, something that works directly with hardware. Other languages uses programs written in c/c++ to run. Python, JS is like placed on higher abstraction layer. For example, for python you need python interpreter which is usually written in C. Chromium core is in c++, and there's JS interpreter inside written in it.
Games only C++, but usually other high-level languages used for scripting, AI, logic.
Web is using languages like PHP, JS, but you can't write a good server in php or js. You can run server from node.js, but node.js is written in C++.