Attach a file versus linked to a related item

I guess I fell behind on keeping up with changes to 1P, but I just discovered that version 8 of 1P now supports attaching a file to an item (a feature that disappeared back in version 7 and whose loss was much mourned) in addition to the newer "link to a related item" feature.

I'm trying to understand exactly how these features differ, and this is what I have discovered thus far:
* with link to a related item, if the original item is moved to another vault, the link to the related item is broken, but in the case of an attached file, the attached file moves with the item
* with link to a related item, the linked item has its own entry, of course, but with an attached file, the attached file is not an "item"

Are there other differences I should be aware of?

After the file attachment feature was removed in 1P7, the migration process turned all the attachments into related items, and then I painstakingly went through my related items and created "back links" to what I considered to be the "parent" item so that when I did a search in 1P and came across a document, from there I could link back to the item to which the document was related. The net result of this is that I have a large number of documents that are their own items, and thus clutter my 1P item list.

In my primary use case for related items (keeping track of registration emails for software licenses), I think that file attaching is a much more natural way to proceed then treating registration emails as a separate document item and then creating relationship links. But, before I go to the time and trouble of converting all these related documents back into attached files, I want to make sure I understand as fully as possible what the implications are of the two methods of associating a file with a 1P item.

---

1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Not Provided
Browser:_ Not Provided