Air NZ does the same thing, but subliminally.
They offer seat selection in Premium Economy, but your choice is - in this case - restricted to adjacent seats between the WC blocks. Or you can pay $75 extra for "access to seating desirable locations" - the pink ones.
The blacked-out seats (and there are more than the image shows) appear to be drip-fed into the inventory as soon as some mug (paying $2700 a seat...) comes up with $75