Is it right to assume that Creative Commons BY-SA was picked over say GPL v2 or v3 because of the attribution requirement it adds beyond just being sharealike?
Also, props for not going with one of the non-commercial variants - the definition of commercial is so debatable, and I'm not sure if it's ever been enforced.
Yes, we do see so many positive contributions from the community - not only on the technical side but also for example environmental justice organisations that build workshop material for students on top of the kit. So we want to make sure that all contributors get attributed.
Also, props for not going with one of the non-commercial variants - the definition of commercial is so debatable, and I'm not sure if it's ever been enforced.