They aren't just for hauling trash, and distributing insulation. Here, I needed to bag insulation, to drag it past a tight obstruction. I could drag three 24"x48" R30 batts in each transit.
Here a messy bed of R19 cellulose interfered with provision of storage in an attic. Things dropped from a deck, into loose-fill insulation, are lost. The central half of the attic floor was cleared into drum liners. Cellulose depth at the periphery would then be doubled, in an upgrade of the attic to R38, adding only batts under decks.
More area at the periphery was tossed clean of cellulose to repair deficient floor sealing, and bare areas were then refilled from the drum liners.
The air duct in the photos above is the supply to a Heatilator gas fireplace, added after house construction. The duct was thoughtlessly placed at a soffit vent, with removal of a vent baffle. With displaced cellulose, the baffle was reset, now using 2x4 blocks instead of just tapping in nails. It was interesting in this young house, to see confirmation of some of my ideas for older homes. Baffles should be plywood. Never cardboard or polystyrene. Kneewall closet walls are solidly clad outside with plywood or with OSB sheathing.