Seth Godin opines (I think) that book covers are stupid, unnecessary
and a waste of money. [
Link]
But I don't know of anyone who has ever
complained that their favorite book has a cover — except when it is
poorly designed and/or manufactured.

Clearly, many customers are willing to buy songs without artwork. But
does that mean they wouldn't want the artwork if it were included in
the sale?
But the issue, to me, is opportunity. Opportunity to communicate with
the customer in more than one media, about a product they either like
or are considering to purchase. That's a good thing in my view.
One thing we are beginning to tinker with at Generator is including CD
booklets for other artists when we ship a customer's order. It costs
our client a few pennies, no additional postage, and the customer gets
to have the booklet if they decide to purchase the digital music —
which, as luck would have it, we are selling at the artist's web store.
I guess what is frustrating to me is this growing sense that many
believe marketing — and profit-making — is somehow bad. As if the world
would be better without it. As if those who practice these tasks are
almost unethical and immoral. It's nonsense!
But more importantly, it is not going away, nor should it. This idea
that somehow the web is going to eliminate print — and by extension
eliminate marketing — is frivolity.
I have been quoted as saying, The future will look a lot like the past.
I predict when everything washes out, companies will discover how to
create web-delivered content with great value and a fair (and dare I
say profitable) price. Customers will gladly pay that price to get what
they want.
And yes, packaging will play a fundamental role in that
process.
Maybe even packaging that (gasp) is printed on paper!