Originally Posted by skywardhunter

It's not the sole purpose. It makes the workload easier on the crew. It might even require fewer crew to be on-duty, not sure of the legal requirements of closed off sections, if they still count towards the seat to crew ratio.

I think moving J to the forward section would have required way more re-engineering and involved more costs. This also makes the aircraft more flexible as presumably they can decide relatively late in the production how to outfit the aircraft, I think the only consideration there is whether they have the structural reinforcement for the weight of the F class seats.