> The HN title makes it sound like differences between the brain and ANNs were previously unknown and is misleading IMO.

Agreed on both counts. There's nothing surprising in "there are differences between the brain and ANN's."

But their might be something useful in the "novel theory about how the brain solves the credit assignment problem" presented in the paper. At least for me, it caught my attention enough to justify giving it a full reading sometime soon.