Repeat grid is ALMOST awesome.
The repeat grid is awesome EXCEPT for the fact that it puts all of the objects on the same layer when expanded. This doesn't work.
I'm trying to make stickers with a dieline. It laid and and spaced them wonderfully except now I have to go back and manually fix the dielines that are now on the same layer as the art. Lame. No thanks, going back to the old way by hand and replicating a correct object.
So you grab your objects and you dielines, located on separate layers, and apply Object > Repeat > Grid (or any other), right? When you do this, both object get moved to a special 'Repeat' container... which is obviously a single entity that can be located at one layer only, as any other object in Illustrator.
Therefore yes, a repeat object can’t be located at two layers at once, and undoubtedly will never can.
You should apply repeats separately for each layer’s art.
And I don’t think that moving dielines to a separate layer after expanding is such a big effort. If you use a specific spot color for these, you can select one, then Select Same Stroke Color and move them to a layer needed easily.