@perler Wow, that is a very good catch!
The kind of; "huh, why have I not thought about this one before, yet it seems obvious"... As you say it, the idea comes from an instant need once in front of a specific situation which requires a solution that no one seems to have a previous need.
And while reading how you describe it, in pops in mind like; "yeah, that would be master piece to be able to restore the files only, in an app as Nextcloud". So true.
There could be others apps as well, but at first thought NC is the very first candidate for such desirable feature, because of the very nature of the app which holds files, and potentially team communications and email boxes as well. And this is where we can see that restoring the whole pack at once, especially for a well active NC app, could produce unexpected outcomes. Depending of course on how the app is used inside an organization.
I don't think it would be a required feature for all apps. But then, if it's easier to implement as a general backup feature then why not. I would vote for this.
Thanks for the heads-up.