The strengthening of insulin spikes ruin the effects of following the other rules.

Stabilizing blood sugar (that cannot be done perfectly, but lowering the amplitude of the variations) will cool down an often hyperactive pancreas that releases too much insulin too fast, causing great damage to your efforts to lose fat.

This is also very much recommended to reduce risks of diabetes (people with large amounts of abdominal fat have a 30% chance of developping diabetes).

A good diet is not about excluding carbohydrates. There is a big difference between stabilizing sugar intake and eating no carbs at all.  Off balance diets (ketonic, low carb, high protein) do more damage than good in the long run.

Naturally, if you eat too much, then it will be necessary to lower intake, but not until you have correctly prepared yourself for that (that is what all the other rules are about).

But diet restrictions do not need to be severe to achieve the results you want.  If they were, it would be impossible for you to maintain them over time.

Stabilizing blood sugar is essential for acquired results to be maintained.  It also helps control hunger, along with a variety of other methods (everything is interlinked).