Couch is next to the wall. That is always bad for sound. Front heights add a LOT to the overall stage. Given your seating position, I'd opt for them instead. Atmos is to seem "above", not behind, and since you have no behind, fronts will give you a bigger presentation IMO.
I find it very interesting what it did for me. There are some scenes where there are more directed sounds, adding to movement around the room, however there are FAR more situations were ambient sound and some of the backgound music is routed to those speakers: "ATMOShere"
The result was unexpected for me that it gives an even bigger "wall of sound" illusion to my ears.