I guess it is mostly the subjective comfortableness of python (and the capacity of throwing prototypes for a team who has only python skills). In my experience

I guess it is mostly the subjective comfortableness of python (and the capacity of throwing prototypes for a team who has only python skills). In my experience all these frameworks end up lacking at some point and becoming leaky abstractions sooner than later. I wish they would work because all the front end technologies require lots of training and skill in order to produce a production ready UI.