The effect on insulin resistance is mostly due to a caloric deficit / lowering of circulating triglycerides, but I think there is a study showing a slight advantage with IF, so you're right on that one, but it's not really a huge difference.
Interesting about the lunches! Are you sure though that it isn't a food intolerance you're dealing with? Often when people cut out foods and say they feel better it's because they're not eating a food that bothers them.
Likely this also included people who just don't eat breakfast because they don't feel like it, which probably also includes people who have a honey bun and a cigarette for lunch and McDonald's for dinner. The results of the study also don't match up with other studies showing a positive result on health markers.
There's nothing magical about intermittent fasting. It won't make you live longer, does nothing cool with your hormones, or any of that nonsense. But it is also a convenient, legitimate way for some people to reduce their overall caloric intake. Reducing caloric intake (and in turn losing fat) results in the improved health markers mentioned above.
Highly re-watchable. It starts off good and just gets better.