I am wondering, what is the reason behind adding a dust jacket when a book has a hardcover as well.
Initially, the purpose seems to be obvious: to protect the hardcover below it, so that it does not get worn out with time. However, the idea of protecting something quite durable with something way more fragile while using this outer, fragile layer also as a medium for the visual design actually seems to deteriorate the design.
I have some books on my shelves that have dust covers - most of them are already torn somewhere, some severly, which makes them look bad:
in case of some or these, the hardcover below has exactly the same visual on it, so by getting rid of the dust covers, I would achieve more neat look of these,
unfortunately, in case of some other ones, the hardcover below is different, less descriptive and elegant; in case of these, removing the dust cover would deteriorate the recognizability of them.
At the same time, most of the hard-covered books I own, even though scrathed sometimes, are in a way better condition.
So, I find the situation like this:
if a dust cover shows the same picture as the hardcover below - it deteriorates the design, as in fact user ends up with a less durable outer part of the book, responsible for the visual presentation of it.
if a dust cover shows a picture, but the hardcover below is missing it - it disadvantages the design even more, as user is also made to make a choice between worse recognizability or more neat look.
So, what is the point of dust covers?