There are some people who have a bias against the use of scripting/interpreted languages for entire applications. The wisdom of this bias is entirely up to individual context.
Scripting languages tend to run a little slower than compiled languages, and in some instances this difference in performance is a huge issue. In most contexts, though, it is a negligible concern.
Python is perfectly well suited for writing applications of all kinds. Using Django or another web framework allows you to build web-based applications. There is nothing deficient about Python in terms of the tools and capabilities needed to write full-scale applications. In fact, Python is arguably much better suited to such work than either PHP or JavaScript, both of which are frequently used for large, complex web applications.