Although there are many sweet rolls in Europe, you will be surprised to see the wide selections of sweet rolls in Japan. You can find dozens of sweet rolls at supermarket. However, there is also a difference not just the selection.
The big difference between European and Japanese sweet rolls is that how it is sold. Usually European one is sold at bakery or supermarket and it is not wrapped. Therefore customer or the shop assistant has to put the sweet roll into a plastic or paper bag each time. Then, they have to remember what is the sweet roll upon at the cashier due to the price can be varied among the sweet rolls. Also, you can hardly know the ingredients.
On the other hand, Japanese sweet roll sold at convenience stores or supermarkets are already placed inside a plastic transparent bag. Therefore, it is better more hygiene reason. Then, you do not have to remember the item due to there is a price tag or barcode on the item. Also the ingredients and other necessary details are mentioned too.