Calling two things “identical” may mean that their concepts are indistinguishable, or that predicates concern one and the same existing subject. Those claims are not equivalent.
Conceptual identity: treating knowledge and power as having precisely the same meaning.
Unity of subject: attributing knowledge and power to one subject despite different meanings.
God is described as knowing and powerful. Both predicates concern one God, but the meaning of knowing does not become the meaning of power. The nuanced formula safeguards the distinctive contents of the attributes while retaining one divine subject.