Only having a couple picatinny rail spots makes zero sense to me on the top tail. And most likely for the manufacturer.

Just because u don't use them, your willing to give up the most basic modularity function of an AR style rifle?

I'd say the top picitinny rail is far more important than any other keymod or M-Lok style connection elsewhere on the rifle. Not sure if it would even save that much weight in the end.