Agree. Non planar 3d printing has been worked on for some time https://www.youtube.com/watch?v=XKVyBa8J3eQ .
I like the fact of having a precise 6-axis arm that could combine additive, subtractive manufacturing.
In addition I was also wondering if it would make sense to have a fixed nozzle and the arm is moving the plate. This would increase the printing angles and allow for very flexible shapes.