That was Sega of Europe's idea. I forget what American Dreamcast games looked like (I had a copy of Q3A on a US disc so I could modify the dial-up settings in the days before Dreamkey 3 came out here), and I think Japanese games just came in normal CD jewel cases.
But yeah, those European cases. I guess they looked quite spiffy back in '99, but you'd better hope nobody between you and your customer doesn't drop the thing because however many layers of bubble wrap you wrap it in, the inertia of that disc in freefall will break through those clips that hold the disc in once it hits the floor. And if anyone opens the case without absolute care will snap off those hinge clips in an instant.