My quick 2 cents is, it depends on what kind/size of fish you are providing structure for. Dense and fluffy stuff helps the smallest guys (fry) and larger and looser the bigger guys (LMB waiting in ambush). I've read some of the Pond Boss crew that raise CC and BC add barrels for spawning structure.
It's not meant to drive you crazy by saying 'it depends', but it kinda does. I bet some species of critter would put that structure to use!
