My kids’ private school has started using it this year.
I’m pretty sure that is why we are having problems with 11th grade US history. It’s the strangest class we’ve ever had at the school. It’s mostly projects outside of class. The class time is spent reading “primary sources” which are things like journals or other first hand accounts of what was going on at the time.
I think they are using it in English also, but that teacher is more experienced.
I can see using primary sources for research. That’s a good idea. I think the math curriculum is nuts.
Maybe your school is picking and choosing what they want and doesn’t buy into the whole curriculum.