You have to fuck around with the storage format because by default scanning sofware, even when scanning documents, will basically just take poorly compressed high resolution images. Maybe there's some service which sorts that out for you but so far I have a little webapp which stores an index of paper copies. Once I figure out how to automate scanning, compressing and OCRing documents then I think it will be worth storing digital copies. But for now it works.

I still do a 3-2-1 backup of documents with 2 versioned backups, one at home and one in another cloud provider, just like with photos.

The archive however is the recovery if I’m not able to retrieve my normal cloud copy (hacked, ransomware, loss of credentials, etc), I cannot access my local mirror copy (ransomware, dead disk, etc), I cannot access my local backup (dead disk, separate from the mirror disk), and I cannot access my cloud backup either.

For all of those things to go wrong a the same time, something major has to happen. Besides, where I live, most required documents (drivers license, passport, birth certificate, tax records, etc) exists in government databases, so all I have at home will be various documents that maybe have sentimental value, but not exactly needed.

Furthermore, documents change “frequently” where photos tend to be somewhat more static, so I can archive photos, and maybe get <10% “duplicates” due to later edits, archiving documents will pretty much be a lot of duplicates each year.

That being said, I think we have like 1GB documents in total, so it would be easy to fit in the archive.

I do occasionally want to retrieve older documents. As you say, they're smaller and the effort to put individual docs into a "I might want this someday" folder seems more trouble than it's worth. Of course, having a vast sea of basically write-only docs does make finding things harder especially as I don't put as much effort into organizing things any longer.