So every interactable object I've found in the game so far has had some purpose. Ropes tied to anything means you can shoot it with a rope arrow and something will happen. Shooting at one tied to doors will allow you to break them down. Shooting at a hanging object (e.g., boxes, torches, etc.) will cause it to swing. One tied to a large pillar means there's a mounting point nearby to create a rope bridge.
But I haven't found the purpose of ropes tied to roofs.
Shooting it when standing on a suspended box doesn't cause you to swing (although it goes against all physics). Shooting it from the ground does nothing as far as I can tell.
What do these things do for me if I shoot at it with a rope arrow?