There are many studies showing that night shift workers experience more mental and physical health issues than day shift workers. Obviously, some things absolutely require night shifts, such as hospitals, but not stores and restaurants. Convenient, sure, but not necessary. So in a socialist country that prioritizes the well-being of workers, do you think these non-critical 24-hour establishments would exist?
Some sources on the health effects of night shifts: 1, 2, 3, 4, 5
To have an efficient society, i don’t think those are necessary. They will waste a lot of resources like labour, electricity and reduce the lifespan of those equipments with electricity. A better solution would be to use technology to ease the work load of workers like in case of restocking that you mentioned. Also have two shifts of workers and let there be breaks for stocking goods. Like during lunch breaks in my country, everything is stalled for an hour.