Why are Requisition Header attachments copied to RFQ Lines instead of RFQ Header?

EBS 12.2.9

When a requester takes the trouble to add attachments to a Requisition Header in iProcurement, why does Buyer Work Center Document Builder copy them to the resulting RFQ Lines, duplicating them, instead of copying them to the RFQ Header? This is the case with "To Supplier" attachments as well as "To Buyer". I haven't tested all types.

I've seen SR responses saying this is by design but what is the rationale? I have requisitions with dozens of header attachments that are now being copied to each line and there are sometimes hundreds of lines. Surely this is a poor design.