These are my opinions for what their worth.
Some fish like Crappie, Bass and other sunfish like to hangout near visable cover or bottom structure and others like Sandbass/Stripers roam open water most of the time.
When we fish Timber and brushpiles we are targeting resting fish, not feeding fish. These resting fish go out and chase shad when they are hungry.
They are also like us, place something suddenly in their face and they will sometimes hit it. They are also competitive, if one hits it often starts the others feeding for a bit.
Trying to attract food to the fish is a waste of time. There's thousands of shad around every brushpile or dock all the time. If the Crappie were hungry they would simply eat the shad.
Fish are also curious, put something new suddenly in front of them and they often try it to see what it is. The only thing they have to test it with is their mouth.
By the way, I fished this morning and caught a nice mess of big Crappie. I guess I got the skunk off. Had to quit at 11:00 wind was terrible.