Benefits? I don't know. I had to work (Kaufland) on Saturday from 6pm to 10pm, and I have to say that I was bored to death after 8pm. My colleague was allowed to go home at 8.30pm because we had no customers, so I was the only cashier. My friend works at Leiser in Berlin's biggest shopping centre. She had to work on Sunday from 2pm to 8pm, they were so "busy" she could go home at 5pm. They girls actually did start fighting for the customers.
The two extra hours are definitely a financial loss for most shops. Well, perhaps the shops in the city had more to do because of the World Cup tourists, but these opening hours definitely make no sense here in the (south) outskirts.

Well, I could go on, but I'm too tired right now and I can't explain it in English; lack of needed vocabulary.