I'm not a big science guy so I won't try to guess any of that. I'm evidence-based in the sense of evidence being how much muscle I have and how shredded I get.
I don't think a single cheat meal / day when on a hard bodybuilding cut diet is doing much for metabolism, particularly if you're already taking T3. We take T3 to combat the metabolic drop from extended hard dieting.
One benefit we can probably all agree on is the increased gym output it gives you for the 1-2 workouts after your cheat. You can train a bit harder, move a little more weight, cardio is easier, so that probably does impact fat loss, but I bet it's incremental. There's also the psychological aspect of seeing yourself bursting at the seams after being really flat for a few days - it's like a preview of that final product you're working towards and that can be very motivating to stay on track.
For me, cheating when on a hard diet is all about the mental impact. I typically go to 0 carbs on weekdays when I'm 1/3 to 1/2 through a diet and as I've stated before my calories get really low - I had a few days last year where calories were around 990 at 230lbs. shredded.
I have no problem sticking to that because I know when the weekend comes we'll go out for brunch, I'll have a big bowl of ice cream / cookies / protein powder, etc. I'm not eating non-stop all day, just 3-4 meals, but it's pretty much whatever I want - no garbage shit like pizza and burgers; more like sushi, fried rice, a big breakfast with an egg scramble / fruit / toast / sausage, etc.
100% diet adherence is a problem for a lot of guys so whatever can fix that is a valuable fat loss tool. I also think it's absolutely ridiculous when guys who don't pay their bills via bodybuilding are so hardcore they can't ever have a cheat meal, they can't go out with friends, etc. That's not a truly enjoyable way to live for most but many guys delude themselves into thinking it is and miss out on a lot of great life experiences. One meal with friends or wild night out isn't won't radically alter your progress on a diet - if it does, you were already doing other things wrong.