Yeah the night-shift sleep disorder is also a type of jet lag and yes people who work shifts experience jet lag. I have heard of motion sickness and some of the symptoms I highlighted are seen there too. I’ve also done well to highlight that those symptoms may be indicative of jet lag but it doesn’t go as much to confirm jet lag.
The circadian rhythm doesn’t solely regulate sleep. Sleep Homeostasis also comes into play when we’ve not had enough sleep and compensates for lost sleep basically by making us sleep during the day. So yes this is why we sleep during the day.