You are absolutely correct, I believe I confused the request here with another request specific to offline syncing of attachments.
Both of which requests similarly reference ID cards, passports, etc. for access for secure attachments.
So my recommendation would have instead been for offline access of attachments, but I do also see the benefit for this request to providing native attachment viewing functionality in the client.
Absolutely am for this and hope it can be something that can eventually be implemented.