Depends on what you want to optimize / what the bottleneck is.
If you have your shops open around the clock, you can use the real estate more efficiently.
I wonder when was the last time that bankers had bankers hours.
In some areas it's going to be as you say - if you want you can close up on Sunday. In other areas it means that lots of people want any kind of work and huge retail places will offer it - of course you have to work extra hours and every weekend. They can do it, because if you don't take the job, the next person will, because they need to.
The interesting alternative I've seen is limited trading hours on the weekend for shops over the size of X m sq. So you still can buy what you need, just not at the mall.