I believe unread books have a long tradition. I remember some novel we had to read in school, talking about unread books. I believe that was The Great Gatsby (from 1925), where the new-rich people bought books as a status symbol and put them on their shelves. But they never read them and you could tell by how the pages hadn't been separated. (Which was a thing to do back then.)
I believe they're still some sort of a status symbol a century later, albeit a different one. I recently bought a book on Kotlin programming, because I'd really like to be able to program Android apps... But I didn't read it (yet), so currently it's just sitting there, collecting dust. But somehow the act of buying it and having it there, did something for me... It's not a status symbol that I brag with to other people at all. But unless I muster up the time and actually read it, I still can't code Android apps.
In that sense, I think there are various reasons why we collect books. And we're all a bit "new-rich", because information and text is available in abundance in the digital age. And you (and everyone) can easily afford to host a BookStack instance... But is it about the content? Is it useful? Or a status symbol to show off to other people? Or a plaything to tinker with, or like with me and the Kotlin book more wishful thinking than anything else? ... Kind of depends on what you do with it.