Being in a caloric deficit is definitely the most important part of fat loss without a doubt. Any cardio is better than no cardio. But I think there is something to be said about using various compounds and doing cardio in a fasted state, especially the lower body fat someone is.
A bodybuilder with plenty of muscle dieting down from 8% to contest weight has a lot of extra things to deal with like muscle loss and stubborn fat. Sure, they can cut calories even further but the risk of muscle loss increases a lot more at that level. HGH increases lipolysis. There is a reason some people say Hgh Frag doesn’t work and others who love it….Frag must be used in a fasted state. Yohimbine is supposed to help break down fat cells, especially in those stubborn areas. Hgh also has muscle sparring properties. Combined with AAS and other drugs, the bodybuilder can hopefully maintain most of his muscle mass while losing mainly pure fat.
So, I think in scenarios like that, there is an advantage in terms of body recomposition. Even if the amount of calories burned in fasted cardio vs cardio at other times is the same, I think the results could be favorable in the fasted group utilizing these tools. Where the calories come from change the outcome a little when everything else is dialed in. Just as Tren is notorious for having a huge recomposition effect because of the nutrient partitioning, fasted cardio with certain drugs and supplements have a partitioning effect of sorts as well.
Just to note, I have no degrees, certs, or any experience doing a contest prep so take what I say with a grain of salt. I’m just a guy who started working out in middle school and still loves it. I’ve been reading and learning for years and always test different things out on myself. I’ve never dieted to contest condition but have gotten fairly lean a few times in my life.