Even if not using a database, I will always reach for Django over a Flask or FastAPI. Yes, there is more boilerplate when just offering a few memory views, but there is so much ecosystem built around the tooling that the expense is worth it. Just making a form or sending an email from Flask requires a third party library which will never receive the level of maintenance as first-party Django. As an example, the often recommended (still mentioned on the Flask Mega-Tutorial) Flask-Mail package last had a commit in 2014.