Well first of all it depends on the dog
Also, each of those blocks weighs around 30 Lbs or so (13Kg). Plus the weight of the couch which looks to be evenly distributed on 5 blocks on both the front and the back. That's a lot of weight with the force pointing straight downward.
I was wrong to generalize and just say 'a dawg' since a big dog could, but I was talking about a dog that could fit in the holes and move around (see The ThreeOfHearts's comment)
I doubt that a dog that can fit in the holes and roll around could do anything to seriously mess up the couches and harm itself.