- Because it's easy: https://github.com/fogleman/HelloFlask
Those do a lot of the work of starting a new Flask project for you.
With cookiecutter flask, all you need to do to build a new project is: cookiecutter https://github.com/sloria/cookiecutter-flask.git
As a warning, cookiecutter flask and overholt include a lot of stuff. I ended up not using it because it was too much work to change everything to work with oAuth.