I can't see any obvious use for such structure. It's not diffusion, or with very very limited efficiency / scattering. It's too shallow, too wide and bottom of wells are (time) aligned. It's not a good absorber either. Has shallow layers of what looks like foam (Basotect like I guess). Has an office type of false ceiling right above - which are usually very poor absorbers centered around 500Hz to enhance speech clarity in office environments. So it's very unlikely the interaction of the back of the suspended panel is calculated to have any sort of membrane effect wrt to the false ceiling. And traditional membranes would need a sealed cavity and rockwool like material in there to lower the frequency and widen the Q - to make them work sufficiently well (unlike micro-sloted type of systems that look like membranes but aren't and work at a distance from a bare wall). "Weird" impedance of the ceiling would also make it hard to get any such thing working. The long 'fins' also considerably rigidify the back panel but to a varying degree with various depth and in one axis, in such ways that it would be very difficult to have a any sort of reliable and useful modal behaviour from the back plate.
The back plate is also very thick (looks like 28mm or 30mm), with added rigidity, I can only guess it creates serious LMF & LF issues.
It could be that the area between the fins is opened to some degree though, giving access to ceiling treatment. But why go through all that trouble when there are much more efficient ways to go about these things.
This is unlikely to enhance stereo perception in the back of the room. A good RFZ, or proper wall treatment will do that just fine.
My guess is it's only an attempt at preventing flutter echo (or cleaning it after the facts) at sweet spot. Or plain visual improvisation...