They are useful for visualizing the effective shape and relative dimensions of a molecule, and (because of the rotatability) the shapes of the surface of the various conformers. On the other hand, these models mask the chemical bonds between the atoms, and make it difficult to see the structure of the molecule that is obscured by the atoms nearest to the viewer in a particular pose.
These models are useful for visualizing the effective shape and relative dimensions of a molecule, as well as the different conformations it can adopt due to rotation. However, they do not show the chemical bonds between atoms, making it difficult to see the structure obscured by atoms closest to the viewer in a specific position.