What is the difference in deformation between a set of rigidly connected rigid bodies and a deformable body?

Consider this hinge joint:

In particular, both linkages are rigid and the joint itself is rigid. While the system does have degrees of freedom and is in some sense deformable, the linkages themselves and the joint are not deformable when considered individually, just as a system.

By contrast, a wooden board that bends due to the stress added onto it is clearly deforming. It has passed beyond the rigidity phase and either is in the elastic phase or the plastic phase.

Clearly the ability for these systems to be manipulated are very different. Yet neither system is rigid and each is in some sense changeable.

What is the difference in deformation between a set of rigidly connected rigid bodies and a deformable body?