Django offers a lot of features that Flask doesn't, but most of them have nothing to do with serving web requests at all, like the very full-featured ORM that Django has, and there are replacements for all the parts that Django has and flask doesn't, like SQLAlchemy (which I like better than Django's ORM to be honest).

But I don't think the line count results would've changed that much if you had used Flask - maybe it would have had 20% fewer LoC.