Yeah ..In prehistoric days roller poles used to be called sticks....
If all you are doing is back rolling a spray then laying off in a single up and down makes sense. Laying on in a large N,W, or whatever suits your fancy (get some paint on the wall).. then laying off in sections makes for a lot more speed when doing a cut and roll.
Always ending each lay off pass at the bottom of the wall means that all the paint is finished in the same direction which makes for a more even finished appearance.