To limit the probability of fastening cladding to an inappropriate substrate, which could lead to an inadequate resistance to expected gravity loads and lateral wind loads.
This is to limit the probability of:
This is to limit the probability of harm to persons.
To supersede the fastening requirement stated in Sentence (1) and allow some cladding materials to be fastened to sheathing where the sheathing offers sufficient strength to support the specific cladding material.