[boomlinde]

Calling something "lightweight" typically has nothing to do with what you end up having to do with the library to satisfy your specific use case. Flask is lightweight in the sense that it does comparably little and imposes fewer architectural dogmas. It's not lightweight in the sense that it always entails doing less work to get where you want, and I don't think that's how the word is typically used when describing technology. It's the difference between simple and easy -- Flask is perhaps simple rather than the other (when compared to Django).

In terms of utility and productivity, it all depends on what you want to achieve, of course, and I imagine that Django is a better choice in many cases, but when you already have the wheels you feel like you'd need to re-invent, and those wheels aren't the bells and whistles Django already offers I think I'd prefer using Flask.