Ian Bicking rants about how worthless they are so I don’t have to.
Look, HTML is a much more approachable standard than python code. You have to write HTML to make your site work. Why would you try to move more HTML into python? HTML generation in python sucks — implicitly or explicitly.
I suppose it all depends on the task at hand. If you are building a web^H^H^HGUI application, you need to have an MVC framework that lets you handle the workflow and data validation in addition to actually building the widgets and presenting the whole thing to the user.