Confessions: What's with the Dust Jacket?

Confessions of an Insomniac Book Devourer #15

There are very few things in life as irksome as a dust jacket on a hardcover to me. Despite my overall love of hardcovers (they can take a beating and help tone my arms), the colorful dust jacket is something I never 'got' about books. Yes, it's pretty, but it's fragile and easily mucked up by life in general and/or moving 400 of your books roughly 400 miles to your new place. Beyond that, I find it almost impossible to read the hardcover with them on, especially in cases of the large books I love (A Dance With Dragons, for example). So I end up taking the dust jacket off, placing it on a high shelf where I won't accidentally put something on it, all to read a book where the cover could feasibly been laminated or printed on (as is the case with many picture or resource books).

But the resounding question with me is always 'Why'? Why do we have dust jackets when we can have easier to take care of hardcover books with them glued on? Besides advertising, do they actually serve a purpose that a laminated cover couldn't fulfill? What's up with that?

As usual when I have a question that can't be easily answered, I Googled 'dust jacket' and pulled up a page on Wikipedia (I always go to Wikipedia but never go straight there- because I'm odd and like Googling). Wikipedia claims that the dust jacket dates to the very late 1820s, but it doesn't sound quite like a dust jacket to me, as the ones they mentioned were glued on, much like some of the hardcovers in my library:

Well, my new ones are more laminated...

As I well knew, dust covers in perfect condition are sought after by collectors. What I didn't know was that those dust jackets can surpass the value of the book itself. There have even been cases of first edition books with dust jackets from later reprints 'married' together, raising the issue of authenticity.

Some of my much abused hardcovers with dust jackets, along with the only perfect dust jacket I have (lower right corner)

As it happens, I've found the original answer to my dust jacket query not from Wikipedia, but from a discussion at User Experience Stack Exchange. The dust cover was to protect the book from dust and other marring, but is now used to cheaply market to different countries that speak the same language, with remarks from critics of those countries (for example, British to Australian, same hardcover, different jacket). That makes a lot of sense to me, but I still wonder at the practicality of the dust jackets. In a way, it would make better sense to keep the jacket separate from the book, preserving the perceived 'more valuable' item.

Personally, I hope people realize that although a dust jacket is cool to look at, it isn't exactly a book. If it came down to it, I'd rather have a first edition hardcover of The Fellowship of the Ring by J.R.R. Tolkien over its pristine dust jacket any day, mostly because as much as I love art, I'd rather be reading the entire book over its blurbs and praises.

Sources and Interesting Information:
Wikipedia "Dust Jacket" page
What is the point of dust covers? discussion at User Experience Stack Exchange
And an interesting Goodreads poll that asks what readers do with their dust jackets (some people apparently throw them away).

How do you feel about dust jackets? Do you read with them on or off? Would you rather have a first edition of your favorite book without a dust jacket, or the first edition dust jacket?