A simple web app will be okay with some HTML forms, sure. But something like a multi step wizard will lead you down the path of storing a huge amount of state on the server side, which turns into a mess. We have a wizard that uses Django's forms and django-formtools's wizard. You have to put the state and complexity somewhere. We put it in the backend and I can't say I like how it turned out. The code is spaghetti and we get a stream of errors from people not acting how they're expected to act.