I have been looking at online-to-print publishing services lately, or alternate formats in e-books, lately. Even with so many online forms, dead-tree formats are still preferred by far. Part of it is a question of format and such, but right now I'm more interested in how people feel about a book.
Stability - It's ironic that in a business world where fluidity and change are pressing forces, that printed books with a fixed set of information are still preferred. It is not as much the permanence as the stability in knowing that the same information is still there, not changing. For a lot of information that does not require adjustments or fluidity, this makes books first in mind. This is also its weakness in books: the more variable information needs to be the less significant the value of a book.
Exclusivity - It is the fact that not everyone can get their work published that adds value to books. This doesn't mean that the best info always gets out there, but it does mean that people have to work harder to get their info published. In the traditional process, this was to encourage excellence (but I don't think that's always the case)
There are other values, but those are being eroded (slowly) with the rise of digital formats: portability, visual impact, artistic value, etc.
Therefore to some folks, its that feeling of exclusivity of having a published book that makes it worthwhile. Which is why I think the idea of vanity publishing used to be compelling enough to keep a cottage industry going. Today however, with key innovations like HP's Indigo press system, it becomes so much cheaper to print low-quantity runs of books.
Take a look at Blurb.com, which allows anyone to get their photos, words, blogs, etc. put into print format at an affordable level. Having written so much over the years, I wouldn't mind taking some of my old online work and having it published into a print format, if nothing else to just have on my bookshelf.