The languages themselves are pretty equivalent. But with PHP it's easier for newbies to grok things when you can just point a web server at a directory that has a "blog.php" file in it, and visit "myserver.com/blog.php" to execute that script and see results. With python you have to understand the basics of what WSGI is and how it works, which is pretty poorly documented for people just starting web development. The "visit a file from my browser's address bar" motif is easier to grasp than "my url gets interpreted as a string that I then parse and route to a function imported from some other file".