ALDI/LIDL are outliers here in Germany. Other supermarket checkouts like Rewe, Edeka, and Kaisers are slower at scanning items. So don't take the speed of ALDI/LIDL cashiers to be indicative of every supermarket checkout in Germany.
Overall, German supermarkets scan items faster than in North America, but ALDI/LIDL are really in their own league. I sometimes think they are faster to scan items than to drop the contents of the belt onto the floor. Impossible to pack in real-time!
For stuff like vegetables and fruits sold by the unit cashiers still pretty much have to learn the codes to be fast. There's a grid overview with images of the groceries and their numbers to help, but eh, you can't look at that or else you are slow.
I still remember that 515 were cucumbers and I believe 529 were 2.5kg of potatoes?...
Because in Germany it's very fast