If Sunday work would only be to increase retailer's profitability then I could not agree more to Nadaix's statement.
Still, one should enlarge the scope of the topic and if I add a little bit of Utopia to it then I see a different picture:
The human body has an internal clock of around 26 hours, i.e. one tends to sleep 1 hour longer every morning and go to bed an 1 hour later every night.
Now what-if everyone's working time shifts by these 2 hours every day, whole year long? E.g. Monday you start at 9am, Tuesday at 11am, etc. and at one stage you start at 11pm,… regardless if its weekday or weekend.
That would then not only result in the shall-we-work-Sundays question, but into the shall-we-work anytime question.
Take the big metropoles like London, Paris or Cologne/Duisburg, etc.:
Traffic: every morning/every evening, every Friday/outbound, every Sunday/inbound - same misery.
Shopping/post office/public administration/doctor's appointment: every after work time - same misery.
and many more examples where queuing up is common.
If everyone shifted its workhours by 2 hours everyday anew private life's effectiveness and efficiency would increase massively with a lot of extra time available for the real stuff, like you state of baking a cake, cycling or watching a movie.
But, admittedly this is a bit of Utopia which cannot be implemented - as most people will perceive the shear thought of this change as an unacceptable intrusion to their lifes (albeit the contrary is more likely).