I didn't realize the games were packaged so differently in Europe. Why are the cases larger for the PS1 games?
(Sorry it took me so long to reply. The image wasn't working.)
I attached an image and did a bit of comparing.
To the left is a game in a standard CD style case, didn't have any US Dreamcast or PS1, so I used a light gun bundle copy of Virtua Cop 2. (Saturn games are mostly in cardboard longboxes over here, but I digress...)
Next to it is a PAL Dreamcast game. Charge N' Blast. Didn't realise the rest of the world used smaller cases for these until recently. These are very annoying, and the hinges break easily and cases are hard to come by to replace.
Then there are a few single disc PS1 cases. Like the Dreamcast jewel case, they are about twice the width of a CD case, so you get half as many on a shelf. No idea why, maybe for easy visual separation from the other territories, or safer shipping. Who knows.
First case is Crusader, slightly shorter with black plastic at the top and bottom. Next is Wild Arms, a little taller with clear plastic on the top and bottom, this is much more common. Finally Tekken is in a cardboard case. Which is very strange.