Digipaks and Mini LP sleeve editions of CDs are just much, much, much, much nicer than regular issues in jewel cases but of course it's harder to keep the paperwork in great condition as it isn't protected by a plastic exoskeleton. I tend to keep all of mine separate from the regular jewel cased discs.
An attractive package, often with fairly extensive information booklets is increasingly important as people are getting their digital via downloads or starting to collect vinyl, with CDs being seen as worthless items by many now, despite them being the lossless quality, hard copy edition of that set of digital files.
Of course they aren't cheaper to produce than bunging a booklet and rear inlay in a dirt cheap, generic jewel case.