What is the purpose of an affidavit in defence of a claim?

The reasons of the chambers judge in one of these appeals, Roy v. Krilow, suggest another aim. They suggest that one needs a detailed description of the documents to let the other side see if all relevant documents have been produced. That is a suggestion novel to me, found in none of the cases or books which I have seen. No authority is cited for it. (It is not always easy to see whether at a given moment those reasons for decision discuss producible, or privileged, documents, or both. But the examples given seem to be producible documents.) I seriously doubt that anyone can ever tell much about the completeness of the documents discovered from the affidavit alone, without looking at the producible documents. Different people number and describe producible documents differently. For example, what to one person is a single document with appendices is to another person a series of documents. I have seen affidavits of documents which in good faith tried to describe each individual document, and which affidavits seemed to me to omit relevant documents. But inspection of the producible documents showed me that nothing was missing.