I worked in a casino and I don't think the owners or the design are intentionally trying to fool you any more than a department store would. You are distracted playing games and lose all track of time since it's more engaging than shopping for socks.
Casino design employs various tactics to make players lose track of time, encouraging longer play and increased spending. These techniques include eliminating clocks and windows, using maze-like layouts, and manipulating sensory experiences like lighting, sound, and scent.
I know your point is they don’t do it more than department stores do, and you might very well be right. I think it is probably hard to prove either way.
I've been in plenty of department stores with windows though. And I don't think I've been to any that drew a false sky on the ceiling. Many stores and malls have skylights too, although when they're the translucent ones, they might be also uplit, so you might not notice it's dark outside.
I think there's at least a difference of degree, but I think it's more than that.
Department stores want you to be intrigued and maybe pick up extra stuff on the way to the thing you actually want to buy, but they don't necessarily want you to loiter. Idle loitering doesn't get you more purchases, at least not immediately.
This is different from a casino, where the most likely thing you'll do if loitering is to sit at a table or machine and gamble more.
Why would a casino have clocks are there clocks in most businesses? Everyone and his dog has a watch or more likely these days everyone has a smartphone with a clock on it.
People used to think we pumped oxygen into the casino too. It would be a fire hazard, and expensive to buy oxygen and maintain such a system. The casino where I worked for 13 years was so cheap they took away the kleenex from the staff locker room, downgraded the toilet paper, cut out staff parties.