They installed the marble to let you know they respect the process.
A white marble suggestion box in a government lobby, bolted directly on top of an industrial paper shredder. You can see the shreds through the window at the bottom. Someone ordered this, someone installed it, and a third person signed the purchase order for the marble slab with SUGGESTION BOX carved into it in a font that says “your input is valued.” The funnel between box and blades is seamless. No gap, no pause, no human hand between your written thought and confetti. A slip is going in right now, already half-eaten. Whatever was on it does not matter. It never did. The only honest touch is the transparent shredder window. They could have hidden it.