I am familiar with both Python and C++ as a programmer. I was thinking of writing my own simple web application and I wanted to know which language would be more appropriate for
The only reason you might want to use C++ over Python is when speed is paramount.
If this is going to be your first web-app, you'll probably be ok with just Python, and your development speed will be orders of magnitude better than with CPP.
Django's templating language is far from powerless, to me it actually seems very pythonic. You actually can write pure python in a template(although this is generally not recommended).
Even better, it's possible to replace Django's templating system with the one you like. My personal favourite language for this is HAML.
Here's some data on this: Is there a HAML implementation for use with Python and Django