I think this could be a revolutionary way to think about how 'work' is done in a startup. Short sprints of 2 days with time in between to recharge could work well for some. The time constraint forces you to focus and changes your mindset about what is possible. Maybe not 15 weekends, but a month could be composed of 10-12 solid 'weekend' sessions. To me it would be more about energy-management than time-management.
I agree that it's definitely not about doing 2-day coding binges 30 days per month. February would be tough, for one. In my mind it's about mindset management. It's about not letting that the validation of your idea be pushed off until you've added "just one more feature," and instead about learning to rapidly iterate on the hypothesize, test, validate cycle.
